dashboards/tests/test_api.py

"""HTTP contract: what the pages may assume, and what must never leak.

The behaviours here are the ones a screenshot cannot show: an unconfigured source answering
404 `configured: false` instead of dialling a hostname that does not exist; a bearer token
that stops at the backend; the single write endpoint refusing on every gate; no external
asset the network can fail to deliver.
"""
from __future__ import annotations

import ipaddress
import json
import re
import time
from collections.abc import Iterator
from contextlib import contextmanager
from pathlib import Path
from typing import Any

import httpx
import pytest
from cryptography import x509
from cryptography.x509.oid import NameOID
from fastapi import HTTPException
from fastapi.testclient import TestClient

import store_perf
from auth_client import sign_in
from auth_contract import ADMIN_PASSWORD, FAST_PBKDF2
from card_contract import HOST_SHAPES, assert_card_contract
from dashboards import alerts, auth, certs
from dashboards import app as app_module
from dashboards.api import MIN_PASSWORD_LENGTH, RANGE_SECONDS, _disk_visible, parse_range
from dashboards.app import create_app
from dashboards.collectors import UpstreamError
from dashboards.config import Settings, Target
from dashboards.rates import MIN_WINDOW_SECONDS, RateEstimator
from dashboards.severity import classify
from dashboards.sources import nut
from dashboards.sources.disks import SMART_SERIES, DisksCollector, parse_disks_snapshot
from dashboards.sources.host import HostCollector, parse_host_snapshot
from dashboards.sources.llm import (
    HISTORY_METRICS,
    parse_gufo_metrics,
    parse_vllm_metrics,
)
from dashboards.store import RES_RAW, Event, Sample, SampleStore
from rate_window_contract import LLM_WINDOW, delta_label
from slots_contract import (
    CANONICAL_TASK_ID_FIELD,
    OPTIONAL_NEXT_TOKEN_FIELDS,
    OPTIONAL_ROW_FIELDS,
    REQUIRED_NEXT_TOKEN_FIELDS,
    REQUIRED_ROW_FIELDS,
    TASK_ID_ALIASES,
    USER_CONTENT_FIELDS,
    load_slots_capture,
)

# refused immediately, and never dials out of the test environment
DEAD_URL = "http://127.0.0.1:1"

#: Every dashboard route, in nav order. The markup pins below (no CDN, no `.sev-*`, no
#: narration, no orphan `id`) run across this list rather than a hand-written four, so a
#: fifth page cannot join the masthead and skip the checks the others had to pass.
PAGES = ("/", "/system", "/disks", "/llm", "/ups")

#: `/settings` is a **page** and not a dashboard (phase 11): it carries the same masthead with
#: no `aria-current` tab, and the account link in every dashboard's masthead is how you reach
#: it. Kept out of `PAGES` because the pins over that tuple assert tab structure — one current
#: tab, a fixed tab order — which this page deliberately does not have. `MARKUP_PAGES` is the
#: list for the checks that are about the bytes rather than the nav.
SETTINGS_PAGE = "/settings"
#: `/certs` is the second admin page (phase 15 task 05), kept out of `PAGES` for exactly the same
#: reason: it is not a tab. It is in `MARKUP_PAGES` and `PAGE_SCRIPTS`, so the CDN, `.sev-`,
#: flavour-text and orphan-`id` audits cover it like the five dashboards.
CERTS_PAGE = "/certs"
MARKUP_PAGES = (*PAGES, SETTINGS_PAGE, CERTS_PAGE)


@contextmanager
def build_client(tmp_path: Path, monkeypatch: pytest.MonkeyPatch, *, simulate: bool = False,
                 **overrides: Any) -> Iterator[TestClient]:
    """A TestClient whose lifespan runs, against a private DB and no real network.

    The store is injected, so `create_app()` deliberately does not close it (production
    owns its own); the caller here does, or every test leaks a SQLite handle and the
    `--cov` log fills with ResourceWarnings that bury the warnings worth reading.
    """
    if simulate:
        monkeypatch.setenv("NUT_SIMULATE", "1")
    else:
        monkeypatch.delenv("NUT_SIMULATE", raising=False)
    db = str(tmp_path / "api.sqlite3")
    settings = Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                        pbkdf2_iterations=FAST_PBKDF2, **overrides)
    store = SampleStore(db)
    client = TestClient(create_app(settings, store))
    client.__enter__()
    try:
        sign_in(client)
        yield client
    finally:
        client.__exit__(None, None, None)
        store.close()


@pytest.fixture
def client(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> Iterator[TestClient]:
    with build_client(tmp_path, monkeypatch) as test_client:
        yield test_client


@pytest.fixture
def ups_client(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> Iterator[TestClient]:
    """NUT on the labelled simulator, actions allowed — the dev configuration."""
    with build_client(tmp_path, monkeypatch, simulate=True, nut_host="127.0.0.1",
                      nut_allow_actions=True) as c:
        yield c


def wait_for_source_error(client: TestClient, key: str, fragment: str,
                          *, timeout: float = 15.0) -> str:
    """Wait for one poll loop to record an error saying `fragment`, and hand back the sentence.

    The poll loops run in the app's event loop, so an assertion about what a source said has to
    wait for a poll rather than read the state at import time. The failure names the last error
    seen, because "it never said that" and "it said something else entirely" are different bugs.
    """
    deadline = time.time() + timeout
    error = ""
    while time.time() < deadline:
        rows = {row["key"]: row for row in client.get("/api/health").json()["sources"]}
        error = str((rows.get(key) or {}).get("error") or "")
        if fragment in error:
            return error
        time.sleep(0.05)
    pytest.fail(f"{key} never reported {fragment!r} (last error: {error!r})")


def wait_for_payload(client: TestClient, path: str, *, timeout: float = 5.0) -> dict[str, Any]:
    deadline = time.time() + timeout
    while time.time() < deadline:
        response = client.get(path)
        if response.status_code == 200:
            return response.json()
        time.sleep(0.1)
    pytest.fail(f"{path} never became available")


def failing_host_payload(scrape: Any, agent_snapshot: dict[str, Any]) -> dict[str, Any]:
    """Two scrapes of the real driveripper capture, nudged onto known sides of the table.

    Driven from the fixture rather than hand-written so a schema drift breaks here first.
    """
    def nudge(snap: dict[str, Any]) -> None:
        snap["memory"]["used_bytes"] = snap["memory"]["total_bytes"] * 0.95   # mem.used_pct -> fail
        snap["cpu_temperature_celsius"] = 91.0                                # cpu.temp_c -> fail
        for fs in snap["filesystems"]:
            fs["used_pct"] = 93.0                                             # disk -> fail

    return scrape(agent_snapshot, cpu_busy=10.0, mutate=nudge)


@pytest.fixture
def data_client(tmp_path: Path, monkeypatch: pytest.MonkeyPatch,
                agent_snapshot: dict[str, Any], host_scrape: Any) -> Iterator[TestClient]:
    """Overview-shaped app: one host payload in the hub plus the simulated UPSes.

    The host job points at a dead port, so a poll can never overwrite the injected payload
    (a failed poll keeps the last good one) — the numbers below are ours, not the fleet's.
    """
    monkeypatch.setenv("NUT_SIMULATE", "1")
    db = str(tmp_path / "summary.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, nut_host="127.0.0.1",
                              admin_password=ADMIN_PASSWORD, pbkdf2_iterations=FAST_PBKDF2,
                              host_targets=(Target("driveripper", DEAD_URL),)), store)
    test_client = TestClient(app)
    test_client.__enter__()
    try:
        sign_in(test_client)
        app.state.ctx.hub.jobs["host:driveripper"].state.payload = failing_host_payload(
            host_scrape, agent_snapshot)
        wait_for_payload(test_client, "/api/ups/snapshot")
        yield test_client
    finally:
        test_client.__exit__(None, None, None)
        store.close()


@pytest.fixture
def healthy_client(tmp_path: Path, monkeypatch: pytest.MonkeyPatch,
                   agent_snapshot: dict[str, Any],
                   host_scrape: Any) -> Iterator[TestClient]:
    """The all-clear app: one host answering on both of its jobs, nothing past a threshold.

    The job's collector is swapped for one that hands back the injected payload, so the
    health record says `ok` truthfully instead of being overridden behind the poller — and
    that has to happen for the `disks` job too, which polls the same dead port: a host is
    either answering or it is not, and a fixture that claims all-clear cannot leave one of
    its two readers failing. Each reader gets **its own** projection of the same capture
    (`parse_disks_snapshot` for the drive page), because a `disks` job holding a `system`
    payload would make `/api/summary`'s drive block answer from the wrong shape and read as
    a passing test that proved nothing.
    """
    with build_client(tmp_path, monkeypatch,
                      host_targets=(Target("driveripper", DEAD_URL),)) as test_client:
        from dashboards.poller import Result  # noqa: PLC0415 - only this fixture needs it

        payload = host_scrape(agent_snapshot, cpu_busy=10.0)
        disks_payload = parse_disks_snapshot("driveripper", agent_snapshot,
                                             DisksCollector()).payload

        async def collect() -> Result:
            return Result(payload=payload, samples=[])

        async def collect_disks() -> Result:
            return Result(payload=disks_payload, samples=[])

        hub = test_client.app.state.ctx.hub  # type: ignore[attr-defined]
        job = hub.jobs["host:driveripper"]
        disks_job = hub.jobs["disks:driveripper"]
        job.fn = collect
        disks_job.fn = collect_disks
        # let the poll already in flight against the dead port land first (it fails in
        # microseconds), then take the health record over: the alerts must describe a host
        # that is answering, not the half-second of startup where it was not
        deadline = time.time() + 2.0
        while time.time() < deadline and job.state.attempts == 0:
            time.sleep(0.02)
        time.sleep(0.05)
        for reader in hub.jobs.values():
            if reader.dashboard not in ("system", "disks"):
                continue
            reader.state.payload = disks_payload if reader is disks_job else payload
            reader.state.ok = True
            reader.state.error = None
            reader.state.consecutive_failures = 0
            reader.state.last_ok = time.time()
        yield test_client


# ---- severity travels with the value --------------------------------------- #

def test_summary_carries_the_verdict_for_every_column_the_page_colours(data_client) -> None:
    body = data_client.get("/api/summary").json()
    row = body["system"]["hosts"][0]
    assert row["severity"] == {"cpu_usage_pct": "ok", "mem_used_pct": "fail",
                               "disk_worst_used_pct": "fail", "temp_c": "fail"}
    # the fleet card is judged by the same table, so amber means the same thing at both
    # sizes — and no GPU verdict, at fleet size or host size (phase 06: busy is the job)
    assert body["system"]["fleet"]["severity"] == {
        "cpu_usage_pct_avg": "ok", "memory_used_pct": "fail",
        "disk_worst_used_pct": "fail",
    }
    for ups in body["ups"]["ups"]:
        assert set(ups["severity"]) == {"charge_pct", "load_pct", "runtime_seconds"}
        assert ups["severity"]["charge_pct"] == classify("ups.charge_pct", ups["charge_pct"])
        assert ups["severity"]["charge_pct"] == "ok", "the simulator starts at float charge"


def test_summary_shape_did_not_shrink(data_client) -> None:
    """Additive-only anchor: /api/summary gained `severity` and lost nothing.

    The overview, the live tests, and any external consumer read the flat keys; this test is
    the tripwire for a well-meaning refactor that "tidies" them away.
    """
    body = data_client.get("/api/summary").json()
    fleet_keys = {"hosts_total", "hosts_live", "cpu_cores", "cpu_usage_pct_avg",
                  "memory_total_bytes", "memory_used_bytes", "memory_used_pct",
                  "disk_worst_used_pct", "load1_total", "net_rx_bytes_per_s",
                  "net_tx_bytes_per_s", "gpu_count", "gpu_busy_pct_avg", "power_estimate_w"}
    host_keys = {"name", "os", "cpu_usage_pct", "load1", "cores", "mem_used_pct",
                 "disk_worst_used_pct", "gpu_busy_pct", "temp_c", "uptime_seconds"}
    ups_keys = {"name", "overall", "status", "charge_pct", "load_pct", "runtime_seconds"}
    assert fleet_keys <= set(body["system"]["fleet"]), fleet_keys - set(body["system"]["fleet"])
    assert host_keys <= set(body["system"]["hosts"][0]), host_keys - set(body["system"]["hosts"][0])
    assert ups_keys <= set(body["ups"]["ups"][0]), ups_keys - set(body["ups"]["ups"][0])
    # `disks` joined in phase 09 and changed nothing else: the set grows, never shrinks
    assert set(body) == {"ts", "system", "disks", "llm", "ups", "recent_events", "alerts"}
    # ...and the new keys are there beside the old ones, not instead of them
    assert "severity" in body["system"]["fleet"]
    assert "severity" in body["system"]["hosts"][0]
    assert "severity" in body["ups"]["ups"][0]


# `/` paints two panels; the payload is still the whole-fleet contract. Every path here is
# read by something that is not the overview page: the live suite, an external probe, a
# notifier later. Deleting a card must never delete a key.
SUMMARY_CONTRACT = ("system.enabled", "system.fleet", "system.hosts",
                    "disks.enabled", "disks.fleet", "disks.hosts",
                    "llm.engines", "ups.ups", "recent_events", "alerts")


def dig(body: dict[str, Any], path: str) -> Any:
    """`body["a"]["b"]` that names the missing path when it is not there."""
    node: Any = body
    for part in path.split("."):
        assert isinstance(node, dict) and part in node, f"/api/summary lost `{path}`"
        node = node[part]
    return node


@pytest.mark.parametrize("fixture", ["client", "data_client"])
def test_summary_serves_every_path_another_consumer_reads(request, fixture: str) -> None:
    """The keys survive the overview cleanup whether or not anything is configured.

    Run twice on purpose: `client` has no targets at all, so it proves the keys are present
    as `None`/`[]` rather than omitted when a source is unconfigured (invariant 3 is about
    the payload shape as much as about colour); `data_client` proves the same paths carry
    the fleet once there is one.
    """
    test_client = request.getfixturevalue(fixture)
    body = test_client.get("/api/summary").json()
    populated = fixture == "data_client"
    for path in SUMMARY_CONTRACT:
        dig(body, path)  # presence is the assertion; a missing path raises with its name
    assert dig(body, "system.enabled") is populated
    assert (dig(body, "system.fleet") is not None) is populated
    names = {host["name"] for host in dig(body, "system.hosts")}
    assert names == ({"driveripper"} if populated else set())
    # the drive-health block is configured exactly when the agents it reads are, and lists the
    # same hosts: a `disks` job exists for every `HOST_TARGETS` entry and for no other reason
    assert dig(body, "disks.enabled") is populated
    assert (dig(body, "disks.fleet") is not None) is populated
    assert {host["name"] for host in dig(body, "disks.hosts")} == names
    batteries = {item["name"] for item in dig(body, "ups.ups")}
    assert batteries == ({"apc", "cyberpower"} if populated else set())
    assert dig(body, "llm.engines") == [], "neither fixture configures an engine"
    assert isinstance(dig(body, "recent_events"), list)
    assert isinstance(dig(body, "alerts"), list)
    # and the payload as a whole still carries every top-level section it always did
    assert set(body) >= {"ts", "system", "llm", "ups", "recent_events", "alerts"}


# ---- alerts: the landing page's answer to "what is wrong" ------------------- #

def test_summary_is_empty_of_alerts_when_everything_is_healthy(healthy_client) -> None:
    """`[]`, not a green banner: an empty list is the clearest possible all-clear."""
    body = healthy_client.get("/api/summary").json()
    assert body["alerts"] == []
    assert body["system"]["fleet"]["hosts_live"] == 1


def test_summary_raises_one_alert_for_the_host_that_stopped_answering(data_client) -> None:
    """One dead host is one line naming it, with the link to the page that explains it."""
    body = data_client.get("/api/summary").json()
    down = [item for item in body["alerts"] if item["source"] == "driveripper"]
    assert len(down) == 1, "its stale payload must not add amber lines on top of the red one"
    assert down[0]["severity"] == "fail"
    assert down[0]["href"] == "/system"
    assert "unreachable" in down[0]["message"]


def test_a_host_that_has_never_answered_is_still_a_row_in_the_fleet(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """A dead agent is a red row in the fleet, not a fleet that quietly got smaller.

    `/api/system/snapshot` already stubs a job with no payload; `/api/summary` has to agree
    with it, or a target that never answered since startup leaves the table at "2/2 hosts"
    while the panel above says a third box is down (`AGENTS.md` invariants 3 and 4).
    """
    with build_client(tmp_path, monkeypatch,
                      host_targets=(Target("driveripper", DEAD_URL),)) as test_client:
        body = test_client.get("/api/summary").json()
        rows = body["system"]["hosts"]
        assert [row["name"] for row in rows] == ["driveripper"]
        assert rows[0]["unreachable"] is True
        assert rows[0]["cpu_usage_pct"] is None, "n/a, never a 0.0 nobody measured"
        assert body["system"]["fleet"]["hosts_total"] == 1
        assert body["system"]["fleet"]["hosts_live"] == 0
        # and the alert list stays exactly one line for it, not a row plus a stale payload
        assert [item["source"] for item in body["alerts"]] == ["driveripper"]


def test_summary_alerts_are_worst_first_and_carry_the_contract(data_client) -> None:
    body = data_client.get("/api/summary").json()
    alerts_list = body["alerts"]
    assert alerts_list, "a dead host plus simulated UPS data cannot read as all-clear"
    for item in alerts_list:
        assert set(item) == {"id", "severity", "source", "message", "href", "at"}
        assert item["severity"] in ("warn", "fail")
    ranks = [0 if item["severity"] == "fail" else 1 for item in alerts_list]
    assert ranks == sorted(ranks), "fails before warns"
    assert any("simulat" in item["message"].lower() and item["href"] == "/ups"
               for item in alerts_list), "NUT_SIMULATE must be said out loud on the landing page"


def test_summary_reuses_the_alert_builder_verbatim(data_client) -> None:
    """The endpoint is a thin call: what `alerts.build` says over the same state is the body."""
    body = data_client.get("/api/summary").json()
    hub = data_client.app.state.ctx.hub  # type: ignore[attr-defined]
    settings = data_client.app.state.ctx.settings  # type: ignore[attr-defined]
    hosts = [job.state.payload for job in hub.jobs.values()
             if job.dashboard == "system" and job.state.payload]
    ups_payload = hub.jobs["nut"].state.payload
    expected = alerts.build(settings, hub.states(), hosts, [], ups_payload, [])
    assert [item["id"] for item in body["alerts"]] == [item["id"] for item in expected]


def test_snapshot_payloads_carry_their_own_severity_sections(data_client) -> None:
    """/api/system/snapshot and /api/ups/snapshot ship the same verdicts the summary reuses."""
    system = data_client.get("/api/system/snapshot").json()
    host = system["hosts"][0]
    assert set(host["cpu"]["severity"]) == {"usage_pct", "temp_c"}
    assert set(host["memory"]["severity"]) == {"used_pct"}
    assert set(host["disks"]["severity"]) == {"worst_used_pct"}
    assert "severity" not in host["gpus"][0], (
        "a GPU verdict came back on /api/system/snapshot — phase 06 removed it"
    )
    ups = data_client.get("/api/ups/snapshot").json()
    for card in ups["ups"]:
        assert set(card["severity"]) == {"charge_pct", "load_pct", "battery_runtime"}
        # numbers keep their own shape; severity is a sibling, never a replacement
        assert isinstance(card["numbers"], dict) and "charge_pct" in card["numbers"]


# ---- the self-test verdict on the two surfaces that were wrong (phase 12) --- #

#: The `ups.test.result` sentences as the hardware answers them. `Done and passed` is the
#: CyberPower's verbatim word from the 2026-10-19 capture (`tests/test_nut.py
#: ::LIVE_SELF_TEST_WORDS`); `FAILED` is what a driver says when a test ran and did not pass,
#: and is the reason the check exists at all. `tests/test_nut.py` pins the *word map*; what is
#: pinned here is the surface `TODO.md:3` names — a warning in the overview's Warnings panel —
#: because a verdict that grades correctly inside `assess()` and still reaches the alert feed
#: as a warning is the same bug wearing a different hat.
SELF_TEST_PASS_WORD = "Done and passed"
SELF_TEST_FAIL_WORD = "FAILED"

#: How `/api/summary` says the check out loud (`alerts._ups_alerts`): `"<check name>: <detail>"`.
SELF_TEST_ALERT_TEXT = "Last self-test"


def set_self_test_verdict(payload: dict[str, Any], status: str, detail: str) -> None:
    """Rewrite every card's `Last self-test` check in the hub's own UPS payload.

    Mutating the payload the job actually serves (instead of hand-building a fake one) is what
    makes this an end-to-end pin: `/api/ups/snapshot` and `alerts.build()` then read the *same*
    object, so the test cannot pass by having the two surfaces disagree about the verdict.
    """
    graded = 0
    for card in payload["ups"]:
        for check in card["health"]["checks"]:
            if check["name"] == SELF_TEST_ALERT_TEXT:
                check["status"] = status
                check["detail"] = detail
                graded += 1
    assert graded, "no `Last self-test` check in the UPS payload — nothing was tested"


@contextmanager
def self_test_app(tmp_path: Path, monkeypatch: pytest.MonkeyPatch,
                  ) -> Iterator[tuple[TestClient, dict[str, Any]]]:
    """A UPS app whose served payload cannot be replaced by a poll mid-assertion.

    The simulated UPSes answer `PASSED`, so the pass direction would survive a race with the
    poll loop and the *fail* direction would not — a test that flakes on a poll is a test of
    timing. Hence `healthy_client`'s trick for the `nut` job: the collector hands back the very
    dict this harness holds, so the health record says `ok` truthfully (invariant 4) and the
    payload stays ours. The interval is shortened for the same reason — waiting a real
    `NUT_INTERVAL_SECONDS` per test would only make the suite slower at proving the same thing.
    """
    with build_client(tmp_path, monkeypatch, simulate=True, nut_host="127.0.0.1",
                      nut_interval=0.5) as test_client:
        from dashboards.poller import Result  # noqa: PLC0415 - only this harness needs it

        hub = test_client.app.state.ctx.hub  # type: ignore[attr-defined]
        job = hub.jobs["nut"]
        wait_for_payload(test_client, "/api/ups/snapshot")
        payload = job.state.payload

        async def collect() -> Result:
            return Result(payload=payload, samples=[])

        job.fn = collect
        # let one poll of *our* collector land before the caller mutates the payload, so the
        # health record and the served bytes are both demonstrably ours
        baseline = job.state.attempts
        deadline = time.time() + 5.0
        while time.time() < deadline and job.state.attempts <= baseline:
            time.sleep(0.02)
        assert job.state.payload is payload and job.state.ok, (
            "the nut job is not serving the payload under test — the pin below would be fiction"
        )
        yield test_client, payload


def self_test_alerts(alerts_list: list[dict[str, Any]]) -> list[dict[str, Any]]:
    return [item for item in alerts_list
            if SELF_TEST_ALERT_TEXT.lower() in item["message"].lower()
            or SELF_TEST_ALERT_TEXT.lower() in item["id"].lower()]


def test_a_passed_self_test_is_quiet_on_the_overview_and_ok_on_the_ups_page(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """The TODO's sentence, end to end: `Done and passed` is not a warning anywhere.

    Both halves of the fix are asserted on one payload: `/api/ups/snapshot` carries the `ok`
    entry the `/ups` check list renders verbatim, and `/api/summary` — the only call the
    overview makes — carries **no** row naming it. The simulated card still contributes its
    `NUT_SIMULATE` line, so the list is not empty and this cannot be a vacuous pass.
    """
    with self_test_app(tmp_path, monkeypatch) as (test_client, payload):
        set_self_test_verdict(payload, "ok", SELF_TEST_PASS_WORD)
        cards = wait_for_payload(test_client, "/api/ups/snapshot")["ups"]
        for card in cards:
            check = next(c for c in card["health"]["checks"]
                         if c["name"] == SELF_TEST_ALERT_TEXT)
            assert check["status"] == "ok", f"{card['name']} reports a pass as {check['status']}"
            assert check["detail"] == SELF_TEST_PASS_WORD, "the driver's word is the useful half"
        rows = self_test_alerts(test_client.get("/api/summary").json()["alerts"])
        assert rows == [], f"a passed battery test is on the overview as {rows}"
        assert any(item["source"] == "ups" for item in
                   test_client.get("/api/summary").json()["alerts"]), (
            "the simulated-UPS line disappeared, so this assertion has nothing left to be quiet about"
        )


def test_a_never_tested_battery_is_not_an_alert_either(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """The APC's factory `No test initiated` reaches the overview as silence, not amber.

    This is the state the live hardware is actually in on one of the two UPSes, so the
    screenshot proves the absence of a warning for a *never-run* test while the payload pin
    above proves it for a passed one. `unknown` is not a verdict an operator can act on, and
    `alerts._RANK` admits only `fail` and `warn`.
    """
    with self_test_app(tmp_path, monkeypatch) as (test_client, payload):
        set_self_test_verdict(payload, "unknown", nut.NEVER_TESTED_DETAIL)
        cards = wait_for_payload(test_client, "/api/ups/snapshot")["ups"]
        assert all(next(c for c in card["health"]["checks"]
                        if c["name"] == SELF_TEST_ALERT_TEXT)["status"] == "unknown"
                   for card in cards)
        assert self_test_alerts(test_client.get("/api/summary").json()["alerts"]) == []


def test_a_failed_self_test_still_reaches_the_overview(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """The check keeps its reason for existing: a test that failed is a red line, once per UPS.

    Without this direction the absence test above is satisfiable by deleting the check, which
    is the failure mode the phase's completion criterion calls out.
    """
    with self_test_app(tmp_path, monkeypatch) as (test_client, payload):
        set_self_test_verdict(payload, "fail", SELF_TEST_FAIL_WORD)
        names = {card["name"] for card in
                 wait_for_payload(test_client, "/api/ups/snapshot")["ups"]}
        assert names, "no UPS card to fail"
        rows = self_test_alerts(test_client.get("/api/summary").json()["alerts"])
        assert {row["source"] for row in rows} == names
        for row in rows:
            assert row["severity"] == "fail", f"a failed battery test reads {row['severity']}"
            assert row["href"] == "/ups", "the alert must link to the card that names the UPS"
            assert SELF_TEST_ALERT_TEXT in row["message"] and SELF_TEST_FAIL_WORD in row["message"]
            assert row["message"].count(SELF_TEST_ALERT_TEXT) == 1, (
                "the row names the check twice — see alerts._clean_error")
        assert all(row["id"] == f"{row['source']}:health:{SELF_TEST_ALERT_TEXT}" for row in rows)


def test_the_ups_check_list_needs_no_new_markup_for_a_passed_verdict(client) -> None:
    """Task 03 expected no page change, and this pins *why* there is none.

    `page-ups.js` puts `check.status` straight on the `<li>`, and `dash.css` colours only the
    `.mark` glyph from the shared `--ok`/`--warn`/`--fail` tokens while the check's name and
    detail stay `--text`/`--text-muted` — so an `ok` row is quiet ink with a tick, and a verdict
    fixed in `assess()` is a verdict rendered. Nothing on either asset names the self-test
    check, which is the point: a special case added here would be a second opinion about the
    driver's word, and the API already made it.
    """
    js = _code(client.get("/static/page-ups.js").text)
    assert '<li class="${check.status}">' in js, "the row no longer wears the payload verdict as its class"
    for verdict in ("ok", "warn", "fail", "unknown"):
        assert f"{verdict}: '" in js[js.index("const MARKS"):], f"MARKS lost the {verdict} glyph"
    rows = js[js.index("const health = item.health"):js.index("const commands = item.commands")]
    assert "self-test" not in rows.lower(), "the check list grew an opinion about one check by name"
    css = _code(_css(client))
    ok_rule = re.search(r"ul\.checks li\.ok \.mark \{([^}]*)\}", css)
    assert ok_rule and "var(--ok)" in ok_rule.group(1), "the ok tick is not the shared token"
    assert "ul.checks li.ok {" not in css, "the whole ok row is coloured — a pass is not a banner"
    assert "self-test" not in css.lower(), "the stylesheet special-cases one check by name"


# ---- unconfigured: say so, and do not dial -------------------------------- #

def test_config_reports_every_source_as_off(client) -> None:
    body = client.get("/api/config").json()
    assert body["system"]["enabled"] is False
    assert body["system"]["targets"] == []
    assert body["disks"] == {"enabled": False, "interval_seconds": 300.0,
                             "timeout_seconds": 30.0}, (
        "the drive-health page is configured exactly when the host agents are")
    assert body["llm"]["gufo"]["enabled"] is False
    assert body["llm"]["vllm"]["enabled"] is False
    assert body["ups"]["enabled"] is False
    assert body["ups"]["actions_enabled"] is False
    assert body["ranges"], "the page builds its window buttons from this list"


def test_health_with_nothing_configured_is_not_a_failure(client) -> None:
    """Nothing configured is 'empty', not 'broken' — and the page must not go red."""
    body = client.get("/api/health").json()
    assert body["status"] in ("ok", "empty")
    assert body["ok"] is True
    assert body["sources"] == []


def test_the_disk_source_has_its_own_health_record_per_host(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """`disks` is a source of its own, not a field of `system` (phase 09).

    Its own record is what gives the page its own dot and its own staleness, and it is
    also what makes `alerts.py` need a rule: two jobs read the same agent, so one dead
    host must still be one line on the overview (see `test_summary_raises_one_alert...`).
    """
    with build_client(tmp_path, monkeypatch,
                      host_targets=(Target("driveripper", DEAD_URL),)) as test_client:
        sources = {row["key"]: row for row in test_client.get("/api/health").json()["sources"]}
        assert "disks:driveripper" in sources, "no separate record, no separate dot"
        assert sources["disks:driveripper"]["dashboard"] == "disks"
        assert sources["disks:driveripper"]["label"] == "driveripper"
        assert sources["disks:driveripper"]["configured"] is True
        assert sources["host:driveripper"]["dashboard"] == "system", (
            "the system job is still its own source: one slow SMART poll must not "
            "decide whether the host looks alive")


def test_no_targets_means_no_disk_job_that_could_look_broken(client) -> None:
    """No host agents, no `disks` task at all — so nothing red for an unconfigured page."""
    assert client.get("/api/health").json()["sources"] == []


@pytest.mark.parametrize("path", ["/api/system/snapshot", "/api/llm/snapshot",
                                  "/api/ups/snapshot", "/api/ups/commands"])
def test_unconfigured_source_is_404_configured_false(client, path) -> None:
    response = client.get(path)
    assert response.status_code == 404
    assert response.json()["configured"] is False
    assert "detail" in response.json()


def test_summary_still_answers_with_no_sources(client) -> None:
    body = client.get("/api/summary").json()
    assert body["system"]["enabled"] is False
    assert body["system"]["fleet"] is None
    assert body["llm"]["enabled"] is False
    assert body["ups"]["enabled"] is False


def test_unknown_route_is_json_not_html(client) -> None:
    response = client.get("/api/nope")
    assert response.status_code == 404
    assert response.headers["content-type"].startswith("application/json")
    assert "no such route" in response.json()["detail"]

def test_an_upstream_failure_escaping_a_route_keeps_its_own_status(tmp_path: Path) -> None:
    """`collectors.UpstreamError` is the one error type a route may raise to say "upstream".

    The handler turns it into `{ok: false, detail}` with the collector's status (502, or 504
    for a timeout) instead of a 500 traceback, and the message is the collector's already
    redacted sentence. Nothing dials here: the error is raised by the route under test.
    """
    db = str(tmp_path / "upstream-error.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2), store)

    @app.get("/api/_boom")
    async def boom() -> None:
        raise UpstreamError("driveripper: http://127.0.0.1:9120/snapshot timed out", status=504)

    with TestClient(app) as test_client:
        sign_in(test_client)
        response = test_client.get("/api/_boom")
        assert response.status_code == 504, "a timeout stays a timeout, not a 500"
        assert response.json() == {"ok": False,
                                   "detail": "driveripper: http://127.0.0.1:9120/snapshot "
                                             "timed out"}
        assert "no-store" in response.headers["cache-control"]
    store.close()


# ---- tokens --------------------------------------------------------------- #

def test_agent_tokens_never_reach_the_browser(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setenv("NUT_SIMULATE", "")
    targets = [Target(name="driveripper", url="http://driveripper:9120",
                      headers={"Authorization": "Bearer SEKRIT-TOKEN"})]
    db = str(tmp_path / "tokens.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2,
                              host_targets=tuple(targets)), store)
    with TestClient(app) as client:
        sign_in(client)
        body = client.get("/api/config")
        assert "SEKRIT-TOKEN" not in body.text
        target = body.json()["system"]["targets"][0]
        assert target["name"] == "driveripper"
        assert "SEKRIT" not in target["url"] and "@" not in target["url"]
        # and a host that never answered stays in the list, marked, with the fleet card intact
        snapshot = wait_for_state(client, "/api/system/snapshot")
        assert snapshot["hosts"][0]["name"] == "driveripper"
        assert snapshot["hosts"][0].get("unreachable") is True
        assert snapshot["fleet"]["hosts_total"] == 1
        assert snapshot["fleet"]["hosts_live"] == 0
        assert snapshot["fleet"]["memory_total_bytes"] is None
    store.close()


def test_a_dead_host_never_writes_its_token_into_the_feed(tmp_path: Path) -> None:
    """The second path a credential can take to a browser: the failure message.

    `parse_targets` moves a userinfo token out of the URL and into a bearer header, so the
    documented `HOST_TARGETS` path never puts one in `Target.url` — this is the backstop for
    any `Target` that does (a hand-built one, a future parser), and the message path is where
    it would matter: the poller keeps an `UpstreamError` string in the health record and logs
    it as an event, so a userinfo-bearing URL there would sit in SQLite and be served on
    `/api/events` forever (AGENTS.md invariant 6). Asserted on every endpoint a page reads,
    not just `/api/config`.
    """
    db = str(tmp_path / "dead-host-token.sqlite3")
    store = SampleStore(db)
    settings = Settings(
        db_path=db,
        admin_password=ADMIN_PASSWORD, pbkdf2_iterations=FAST_PBKDF2,
        host_interval=0.05,
        host_targets=(Target(name="driveripper", url="http://SEKRIT-AGENT-TOKEN@127.0.0.1:1"),),
    )
    with TestClient(create_app(settings, store)) as client:
        sign_in(client)
        deadline = time.time() + 10
        while time.time() < deadline:
            health = client.get("/api/health").json()
            if health["sources"] and health["sources"][0]["error"]:
                break
            time.sleep(0.05)
        else:
            pytest.fail("the dead host never recorded an error")
        for path in ("/api/health", "/api/events", "/api/system/snapshot",
                     "/api/disks/snapshot", "/api/summary"):
            body = client.get(path).text
            assert "SEKRIT-AGENT-TOKEN" not in body, f"{path} leaked the agent token"
        # and the outage is still legible — redaction is not the same as silence
        assert "driveripper" in client.get("/api/health").text
        assert "unreachable" in client.get("/api/events").text
        # the `disks` job dials the same token-bearing URL on its own cadence, so its
        # sentence is a second copy of the same risk: `fetch_snapshot` is the one place
        # either dashboard builds a failure message, and it uses the redacted URL
        disks_state = next(row for row in client.get("/api/health").json()["sources"]
                           if row["key"] == "disks:driveripper")
        assert disks_state["error"] and "SEKRIT-AGENT-TOKEN" not in disks_state["error"]
        assert "127.0.0.1:1/snapshot" in disks_state["error"], "the failure still names where"
    store.close()


def test_a_revoked_agent_fails_both_of_its_sources_without_a_dial(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """The chain end to end, wiring included: revoke it, and the next poll stops talking to it.

    `collectors.agent_tls_map` is what `build_hub` hands the jobs, so this is the proof that a
    revocation reaches a *running* app through its own `meta` table — no restart, and no second
    process telling the first. The spy replaces `httpx.AsyncClient.get` on the class, so it
    catches the shared client and the per-dial TLS client alike: what must not happen is any
    request at all, because a dial that then gets refused still put a socket on a host the
    operator struck out.
    """
    db = str(tmp_path / "revoked-agent.sqlite3")
    store = SampleStore(db)
    settings = Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                        pbkdf2_iterations=FAST_PBKDF2,
                        host_interval=0.05, disks_interval=0.05,
                        host_targets=(Target(name="deskwork", url="https://127.0.0.1:1"),))
    with TestClient(create_app(settings, store)) as client:
        sign_in(client)
        # Before the revoke the same dead host fails as an unreachable upstream. That sentence is
        # the control: it is what a dial produces, so the one after it has to mean something else.
        wait_for_source_error(client, "host:deskwork", "unreachable")
        state = certs.issue_agent_cert(store, certs.ensure_certs(store), "deskwork",
                                       ["127.0.0.1"])
        certs.revoke(store, state, "deskwork")

        calls: list[str] = []

        async def spy_get(self: Any, url: Any, **kwargs: Any) -> Any:
            calls.append(str(url))
            raise AssertionError(f"a revoked agent was dialled at {url}")

        monkeypatch.setattr(httpx.AsyncClient, "get", spy_get)
        for key in ("host:deskwork", "disks:deskwork"):
            error = wait_for_source_error(client, key, "agent certificate revoked")
            assert "unreachable" not in error, "the refusal replaced the dial's sentence"
        assert calls == [], "the gate is in front of the network, not behind it"
        # and the overview says the operator revoked it rather than that the box went down
        messages = [row["message"] for row in client.get("/api/summary").json()["alerts"]]
        assert any("certificate revoked" in text for text in messages), messages
    store.close()


def test_engine_urls_are_redacted_the_same_way_hosts_are(tmp_path: Path) -> None:
    """`GUFO_BASE_URL`/`VLLM_BASE_URL` go to the browser verbatim in `/api/config`, and unlike
    `HOST_TARGETS` nothing parses a userinfo token out of them into a header — so a URL that
    happens to carry credentials has to be redacted where it is served (invariant 6).
    """
    db = str(tmp_path / "engine-redact.sqlite3")
    settings = Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                        pbkdf2_iterations=FAST_PBKDF2,
                        gufo_url="http://SEKRIT-ENGINE-TOKEN@deskwork:8731",
                        vllm_url="http://driveripper:8000")
    store = SampleStore(db)
    with TestClient(create_app(settings, store)) as client:
        sign_in(client)
        body = client.get("/api/config")
        assert "SEKRIT-ENGINE-TOKEN" not in body.text
        llm = body.json()["llm"]
        assert llm["gufo"]["base_url"] == "http://deskwork:8731"
        assert llm["vllm"]["base_url"] == "http://driveripper:8000"   # untouched when clean
    store.close()


@pytest.mark.parametrize(("llm_interval", "rate_window"), [(2.0, 10.0), (4.0, 20.0)])
def test_build_hub_gives_each_source_the_estimator_its_own_cadence_fills(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch,
        llm_interval: float, rate_window: float) -> None:
    """Two rate estimators, one per measuring cadence (phase 23, `TODO.md:8`).

    The spy is the point: the numbers themselves are `config` defaults and a test on the default
    would pass even if `build_hub` handed one estimator to both sources. So this asserts the two
    **objects** the jobs receive, and does it at a non-default cadence pair to prove the LLM span
    tracks `LLM_INTERVAL_SECONDS` rather than a second knob nobody configured — one 10 s window
    smoothed a slot start across the five polls the operator was watching (the ramp), and a 2 s
    window over a 10 s `host` poll would answer `n/a` every poll.

    The payload-level twin of this pin is the `Δ<window>` label each rate cell carries: this is
    the wiring, that is what the browser prints (phase 23 task 02 pins the labels).
    """
    seen: dict[str, RateEstimator] = {}
    real_host_jobs = app_module.host_jobs
    real_llm_jobs = app_module.llm_jobs

    def spy_host_jobs(targets: Any, http: Any, host_collector: Any, interval: float,
                      **kwargs: Any) -> list[Any]:
        seen["host"] = host_collector.rates
        return real_host_jobs(targets, http, host_collector, interval, **kwargs)

    def spy_llm_jobs(cfg: Any, http: Any, rates: RateEstimator) -> list[Any]:
        seen["llm"] = rates
        return real_llm_jobs(cfg, http, rates)

    monkeypatch.setattr(app_module, "host_jobs", spy_host_jobs)
    monkeypatch.setattr(app_module, "llm_jobs", spy_llm_jobs)

    db = str(tmp_path / "rate-windows.sqlite3")
    store = SampleStore(db)
    settings = Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                        pbkdf2_iterations=FAST_PBKDF2,
                        host_targets=(Target("deskwork", DEAD_URL),),
                        gufo_url="http://deskwork:8731", vllm_url="http://driveripper:8000",
                        llm_interval=llm_interval, rate_window=rate_window)
    # `build_hub` only wires jobs; nothing here dials, so the shared client is never started
    # and there is no event loop to close one in.
    hub, _nut_monitor = app_module.build_hub(settings, store, httpx.AsyncClient())
    store.close()

    assert sorted(seen) == ["host", "llm"], "a source stopped being handed an estimator"
    assert sorted(hub.jobs) == ["disks:deskwork", "host:deskwork", "llm:gufo", "llm:vllm"]
    assert seen["llm"] is not seen["host"], \
        "one estimator for both cadences is the bug this phase exists to fix"
    assert seen["llm"].span == pytest.approx(llm_interval), \
        "the LLM window must track LLM_INTERVAL_SECONDS, not a second knob"
    assert seen["host"].span == pytest.approx(rate_window), \
        "the host rates keep RATE_WINDOW_SECONDS: a 2 s span over a 10 s poll is `n/a` forever"
    # …and the smaller window still carries the production floor, so the phase-13 refusal of the
    # poll loop's ~0.2 s catch-up gap is not a consequence of the wider span.
    assert seen["llm"].min_window == MIN_WINDOW_SECONDS
    assert seen["host"].min_window == MIN_WINDOW_SECONDS
    assert seen["llm"].span > MIN_WINDOW_SECONDS, "the LLM window would refuse every poll"


def test_config_reports_the_window_the_llm_rates_are_actually_measured_over(
        client: TestClient) -> None:
    """`/api/config`'s llm window is a measurement claim, so it is the LLM's own span.

    It used to echo `RATE_WINDOW_SECONDS` for both sources, which was harmless while one estimator
    served them all. Since phase 23 that same field would have advertised a 10 s window beside
    rates measured over 2 s — a number the page can print and no poll ever used (rule 2).
    """
    llm = client.get("/api/config").json()["llm"]
    assert llm["rate_window_seconds"] == llm["interval_seconds"] == 2.0


def wait_for_state(client: TestClient, path: str, *, timeout: float = 5.0) -> dict[str, Any]:
    deadline = time.time() + timeout
    while time.time() < deadline:
        response = client.get(path)
        if response.status_code == 200:
            return response.json()
        time.sleep(0.1)
    pytest.fail(f"{path} never answered")


def test_target_problems_are_surfaced_not_swallowed(client) -> None:
    body = client.get("/api/config").json()
    assert body["system"]["target_problems"] == []


# ---- the credential the server refuses to start without (phase 11) --------- #


def test_no_verifier_and_no_seed_means_the_server_does_not_come_up(tmp_path: Path) -> None:
    """Fail closed, at the one place a mistake is unmissable: startup.

    Task 03 is what demands a session on every route; this is the half before it — a deployment
    with neither a stored `auth.verifier` row nor `DASH_ADMIN_PASSWORD` must not run open, so
    the lifespan raises instead of publishing a context, starting the pollers, or serving a
    page. Asserting that nothing was written is part of it: "refused" that seeded a row on the
    way out would leave the next start half-configured.
    """
    db = str(tmp_path / "no-credential.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=""), store)
    try:
        with pytest.raises(RuntimeError) as caught, TestClient(app):
            pytest.fail("the lifespan yielded with no admin credential")
        message = str(caught.value)
        assert "DASH_ADMIN_PASSWORD" in message, "the operator's fix is in the exit output"
        assert "auth.verifier" in message and "DELETE FROM meta" in message
        assert not hasattr(app.state, "ctx"), "nothing is published, so nothing can serve"
        assert store.get_meta("auth.verifier") is None
        assert store.get_meta("auth.session_secret") is None
    finally:
        store.close()


def test_the_same_server_starts_once_the_environment_seeds_a_password(tmp_path: Path) -> None:
    """The other side of the gate, so the failure above cannot be satisfied by a broken app.

    With a seed the process comes up, the state hangs off the context (task 03 reads it on
    every request), and both rows are durable — which is also what lets the operator delete
    `DASH_ADMIN_PASSWORD` from the deployment after the first boot.
    """
    db = str(tmp_path / "seeded.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2), store)
    try:
        with TestClient(app) as client:
            assert client.get("/api/health").status_code == 200   # public: the healthcheck
            state = app.state.ctx.auth
            assert state is not None
            assert state.seeded is True and state.env_ignored is False
            assert state.iterations == FAST_PBKDF2
            assert auth.verify_password(ADMIN_PASSWORD, state.verifier) is True
            assert store.get_meta("auth.verifier") == state.verifier
            assert store.get_meta("auth.session_secret") == state.secret
            assert ADMIN_PASSWORD not in state.verifier + state.secret
    finally:
        store.close()


# ---- pages ---------------------------------------------------------------- #

@pytest.mark.parametrize("path,title", [
    ("/", "overview"), ("/system", "system"), ("/disks", "disks"), ("/llm", "llm"),
    ("/ups", "ups"),
])
def test_pages_serve_and_declare_themselves(client, path, title) -> None:
    response = client.get(path)
    assert response.status_code == 200
    assert "text/html" in response.headers["content-type"]
    assert title in response.text.lower()


def test_no_page_loads_anything_from_the_internet(client) -> None:
    """No CDN, no webfonts: this dashboard has to work with no route to the internet.

    `/login` is not in `MARKUP_PAGES` and cannot be: this `client` is signed in, a signed-in
    `GET /login` is a `303`, and following it would audit `/`'s bytes under the wrong name. The
    same fragments are checked against the real login page, unsigned, by
    `tests/test_auth_api.py::test_the_login_page_loads_nothing_from_the_internet`.
    """
    for path in MARKUP_PAGES:
        html = client.get(path).text
        for fragment in ("//cdn.", "https://fonts.", "//unpkg.com", "//cdnjs"):
            assert fragment not in html, f"{path} references {fragment}"


def test_static_assets_are_served(client) -> None:
    for asset in ASSETS:
        assert client.get(asset).status_code == 200, asset


# ---- /settings: the account page (phase 11 task 06) ----------------------- #
#
# `/settings` is the operator's own surface: the session this browser holds, a sign-out, and the
# one form that changes the admin password. Its HTTP surface is tested twice on purpose — the
# route-enumeration test in `tests/test_auth_api.py` proves nothing outside the public list
# answers anonymously (which is how `/settings` is gated for free by being in `PAGES` in
# `app.py`), and the assertions here pin the **page**: the form fields a password manager needs,
# the outcome line that is a live region, the precedence sentence that stops the "I edited the
# env file and nothing happened" support call, and the masthead link that is the only way in.

def test_the_settings_page_carries_the_session_and_the_form(client) -> None:
    response = client.get(SETTINGS_PAGE)
    assert response.status_code == 200
    assert "text/html" in response.headers["content-type"]
    html = response.text
    # the session panel and its way out
    for fragment in ('id="sign-out"', 'id="session-user"', 'id="session-expires"',
                     'id="session-left"'):
        assert fragment in html, f"/settings has no {fragment}"
    # the change-password form: three fields, each labelled, each with the floor spelled out,
    # and the autocomplete values a password manager needs to fill the right one
    for fragment in ('id="current-password"', 'autocomplete="current-password"',
                     'id="new-password"', 'autocomplete="new-password"',
                     'id="confirm-password"', 'id="change-password"',
                     '<label for="current-password">', '<label for="new-password">',
                     '<label for="confirm-password">', 'aria-describedby="password-hint"'):
        assert fragment in html, f"/settings' form is missing {fragment}"
    assert "8 characters" in html, "the form stopped naming the length floor it enforces"
    # the outcome line is announced, because the operator asked for it and nothing else will
    assert 'id="settings-result"' in html and 'role="status"' in html


def test_the_settings_page_states_the_precedence_rule(client) -> None:
    """The sentence that makes the env file's losing half legible on the page that wins.

    `README.md` documents the same rule, but the operator reading it there is deciding what to
    write in a file; the operator reading *this* page just changed a password and needs to know
    why a container env will not undo it.
    """
    html = client.get(SETTINGS_PAGE).text
    assert "DASH_ADMIN_PASSWORD" in html
    assert "auth.verifier" in html
    assert "never overwrites" in html


def test_the_settings_page_is_not_one_of_the_dashboards(client) -> None:
    """The tabs are there to leave with; nothing marks itself current, because nothing is.

    A tab marked current on a page that is not in the tab list claims a location the app does not
    have, and the four dashboards' own masthead pin (`aria-current` exactly once) relies on that
    marker meaning something.
    """
    html = client.get(SETTINGS_PAGE).text
    assert '<nav class="tabs"' in html
    assert 'aria-current="page"' not in html
    for path in PAGES:
        assert f'href="{path}"' in html, f"/settings cannot navigate to {path}"
    # The fleet badges belong here too (`TODO.md:3`): the container is what made them appear on
    # the five dashboards, and a page that renders the masthead without it is the page where they
    # "disappear". `Dash.initChrome()` fills it from `/api/health` exactly as it fills the others.
    assert 'id="nav-status"' in html, "/settings lost the fleet badges the operator asked for"


def test_the_settings_page_refuses_a_caller_with_no_session(tmp_path: Path) -> None:
    """One page-level assertion of the gate, not a second enumeration of it.

    `tests/test_auth_api.py::test_every_route_that_is_not_public_requires_a_session` is the
    general proof; this one exists so a regression in `/settings` names `/settings`.
    """
    db = str(tmp_path / "settings-gate.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2), store)
    try:
        with TestClient(app, follow_redirects=False) as anon:
            page = anon.get(SETTINGS_PAGE, headers={"accept": "text/html"})
            assert page.status_code == 303
            assert page.headers["location"] == f"/login?next={SETTINGS_PAGE}"
            data = anon.get(SETTINGS_PAGE, headers={"accept": "application/json"})
            assert data.status_code == 401
            assert data.json() == {"ok": False, "detail": "sign in required",
                                   "login": "/login"}
    finally:
        store.close()


def test_every_page_links_to_both_admin_pages(client, tmp_path: Path) -> None:
    """`⚙ Account` and `⚷ Certs` are the only way to the two admin pages, so they are everywhere.

    One loop over all seven signed-in pages (`MARKUP_PAGES`), because the control row is the *same*
    on all of them: `⚷ Certs` → `⚙ Account` → theme toggle → clock, in `.masthead-right` and
    **outside** `.tabs` (the tab strip's structure — five dashboards, one of them current — is pinned by
    `test_the_disks_tab_is_in_the_masthead_of_every_page`, and a sixth entry with no
    `aria-current` would break what that marker means).

    Both links are on the pages they name, which **inverts** phase 15's "no self-link"
    precedent on the operator's decision (`TODO.md:4` — "clicking the certs tab causes the certs
    button to disappear … These should remain visible"): masthead chrome that changes shape
    depending on where you already are reads as a broken control, while a link to the page you
    are on is a no-op that answers with the page you were looking at.

    The clock last is phase 25 task 03 (`TODO.md:5` — "The time should show up as the farthest
    right item on the navbar"). It is pinned as **markup**, not as a CSS `order` property, because
    that is what makes the claim true: task 02 left the control row `justify-content: flex-end`, so
    the last child of `.masthead-right` *is* the farthest-right item, and an `order:` override the
    pin could not see would leave this test green over a bar that says something else. (Below 900 px
    the clock is hidden by the long-standing `.clock` media rule — a readout, not a control, so
    hiding it is not the "no control is hidden to fit the width" rule this app keeps — and the
    markup order this test reads is width-independent.)
    """
    account_open = '<a class="ghost account" href="/settings"'
    certs_open = '<a class="ghost account" href="/certs"'
    # the opening tag **and** its label: the claim is the cluster does not change shape between
    # pages, and `/certs` shipped a theme toggle missing its `aria-pressed` for exactly the
    # reason nothing ever compared the seven markups
    account = f'{account_open} title="Session and password">⚙ Account</a>'
    certs_link = f'{certs_open} title="Agent certificates">⚷ Certs</a>'
    theme = '<button class="ghost" id="theme-toggle" type="button" aria-pressed="false">'
    # The other half of the clock claim, from the stylesheet side: no `order:` on anything in the
    # bar, because a re-ordering property would leave this markup audit describing a bar that
    # paints in some other order (`data/logs/25-task03-verify.cjs` measures the painted order at
    # both widths; this is the served-byte guard under that measurement).
    css = _css(client)
    for selector in (".masthead", ".masthead-right", "#nav-status", ".clock"):
        assert "order" not in _declarations(css, selector), \
            f"{selector} grew an `order:` declaration — the clock's place in the row is markup"
    for path in MARKUP_PAGES:
        html = client.get(path).text
        assert certs_link in html, f"{path} has no route to the certificate authority"
        assert account in html, f"{path} has no route to the account page"
        before_theme = html[:html.index('id="theme-toggle"')]
        assert certs_link in before_theme, f"{path} put the Certs link after the theme toggle"
        assert account in before_theme, f"{path} put the Account link after the theme toggle"
        assert before_theme.index(certs_link) < before_theme.index(account), \
            f"{path} orders the two admin controls differently from the dashboards"
        # …and the clock after the toggle, i.e. last in `.masthead-right`: on the `flex-end`
        # control row that is the farthest-right item on the bar (TODO.md:5).
        assert html.index('id="clock"') > html.index('id="theme-toggle"'), \
            f"{path} does not end its control row with the clock"
        tabs = html[html.index('<nav class="tabs"'):html.index("</nav>")]
        assert "/certs" not in tabs, f"{path} made Certs a dashboard tab"
        assert "/settings" not in tabs, f"{path} made Account a dashboard tab"
        assert theme in html, f"{path}'s theme toggle no longer matches the other seven"

    # The one page that renders neither, and its own client: `client` is signed in, and a
    # signed-in `GET /login` is a `303` to the dashboard, which would audit `/` and call it
    # `/login` (the trap documented at `test_the_login_page_carries_no_nav_and_no_toggle`).
    # Pre-auth there is nothing to administer, so the masthead stays brand link + theme toggle.
    db = str(tmp_path / "admin-links-login.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2), store)
    try:
        with TestClient(app) as anon:
            response = anon.get("/login")
            assert response.status_code == 200, \
                "a signed-out /login must be the form, not a bounce"
            login_html = response.text
    finally:
        store.close()
    # the opening tag, so an `href` under any other class or label still fails here
    for link in (certs_open, account_open):
        assert link not in login_html, f"/login offers {link} to a caller who cannot use it"


def test_the_certs_page_is_a_page_and_not_a_sixth_dashboard(client) -> None:
    """`/certs` borrows the dashboard chrome and none of the dashboard meaning (task 15.05).

    Five tabs with nothing current, the four fleet badges like every other masthead (phase 25:
    the badges report the fleet, and that report is the point of the site on this page too), and
    the same head and stylesheet as every other page — this is the
    `test_the_settings_page_is_not_one_of_the_dashboards` assertion for the second admin page,
    and it is what a sixth tab in the strip would fail on.
    """
    html = client.get(CERTS_PAGE).text
    assert html.count('aria-current="page"') == 0
    tabs = re.findall(r'<a href="([^"]+)"[^>]*aria-current="page"', html)
    assert tabs == [], f"/certs marked a tab current: {tabs}"
    assert 'id="nav-status"' in html, "/certs lost the fleet badges the operator asked for"
    for path in PAGES:
        assert f'href="{path}"' in html, f"/certs cannot navigate to {path}"
    assert '/static/dash.css' in html


def test_the_certs_page_carries_the_authority_and_the_agents_table(client) -> None:
    """The three blocks the page is: the root, the client line, and one row per host.

    Pinned on the served bytes rather than on a browser: the root and client panels and the table
    are markup, and the two rows of the table body are built from `GET /api/certs` by
    `page-certs.js` — so the per-row action labels are asserted on the served **script**, the way
    `/ups` pins its command buttons. `tests/test_api.py` has no JS runner (a locked anchor), and a
    label that shipped in neither file would be an invisible button either way.
    """
    html = client.get(CERTS_PAGE).text
    js = client.get("/static/page-certs.js").text

    assert "Root CA" in html and 'id="root-serial"' in html
    assert 'id="root-expires"' in html and 'id="root-left"' in html
    assert "Rotate root CA" in html, "the CA-wide action disappeared"
    assert "Dashboard client" in html and 'id="client-serial"' in html
    assert 'id="client-expires"' in html, "/certs lost the client expiry"
    assert 'id="agents-table"' in html and "<tbody></tbody>" in html
    assert 'id="agents-empty"' in html and "hidden" in html

    for label in ("Rotate", "Revoke", "bundle"):
        assert f"'{label}'" in js, f"the {label} action lost its label"
    for route in ("/rotate", "/revoke", "/bundle"):
        assert route in js, f"the page no longer reaches {route}"
    assert "/api/certs/root/rotate" in js


def test_the_certs_agents_table_scrolls_to_its_last_column(client) -> None:
    """`#agents-table` carries the `.scroll` modifier, and the stylesheet still styles it.

    `TODO.md:9`: at phone width the serial, expiry, `san` and controls columns were clipped by
    `.card { overflow: hidden }` with no way to reach them. `dash.css` turns `table.data` into
    a scroll container **only** through the `scroll` class, so the class and the rule are one
    mechanism and are pinned together — the phase-18 idiom of comparing the two places a
    contract lives, because a rename on either side silently un-scrolls the table.
    """
    html = client.get(CERTS_PAGE).text
    assert '<table class="data scroll" id="agents-table">' in html, \
        "the agents table lost its .scroll modifier — the controls column is unreachable at 360px"

    css = client.get("/static/dash.css").text
    start = css.index("table.data.scroll {")
    rule = css[start:css.index("}", start)]
    assert "overflow: auto" in rule, "table.data.scroll no longer scrolls — the class names nothing"


def test_the_certs_page_prints_the_names_the_authority_mints(client) -> None:
    """The CN of each certificate is markup, so the literal is pinned to `certs.py`.

    `MIN_PASSWORD_LENGTH`'s idiom: there is no build step to share a Python constant with a page,
    so a page that restates one says it in markup and a test compares the two. Printing a CN the
    module did not sign with would be the page inventing a fact about a stored certificate.
    """
    html = client.get(CERTS_PAGE).text
    assert f">{certs.ROOT_CN}<" in html, "the root panel's CN is not what certs.py signs"
    assert f">{certs.CLIENT_CN}<" in html, "the client line's CN is not what certs.py signs"


def test_the_certs_page_reads_only_fields_the_cert_api_publishes(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """End to end, in both directions: the page's column table and `GET /api/certs` are one shape.

    The served script's `COLUMNS` entries name every payload key the page indexes, so this is the
    `SLOT_FIELDS` device on the surface where a rename is worst: a `deployed_bundle_rev` that
    quietly became `agent_bundle_rev` would print `n/a` beside a healthy fleet forever.
    """
    script = "/static/page-certs.js"
    with build_client(tmp_path, monkeypatch, host_targets=cert_hosts(3),
                      host_interval=3600.0) as client:
        js = client.get(script).text
        names: set[str] = set()
        for listed in re.findall(r"fields: \[([^\]]*)\]", js):
            names.update(re.findall(r"'([^']+)'", listed))
        assert names == CERT_AGENT_KEYS, sorted(names ^ CERT_AGENT_KEYS)

        client.post("/api/certs/deskwork/rotate")
        for row in cert_agent_rows(client):
            assert len(row) == 8
            for name in names:
                assert name in row, f"the page indexes `{name}` and the API does not publish it"

        # …and the two authority blocks: the page prints a serial and an expiry for each, which is
        # exactly the key set the API answers there.
        body = cert_document(client)
        for block in ("root", "client"):
            assert set(body[block]) == CERT_TIMESERIAL_KEYS
        for name in CERT_TIMESERIAL_KEYS:
            assert f".{name}" in js, f"the page stopped reading `{name}`"


def test_the_certs_page_never_colours_a_certificate(client) -> None:
    """No severity vocabulary reaches this page at all — an expiry is a date, not a verdict.

    `/api/certs` sends no `severity` anywhere (task 04, and `severity.py` rates no certificate),
    so a page that coloured an expiring cert would be inventing a threshold in JavaScript. The one
    colour on the page is the payload's `status` word through a word→class map, and `unissued`
    maps to no class at all — a certificate that does not exist must not borrow green.
    """
    js = _code(client.get("/static/page-certs.js").text)
    assert "severity" not in js, "/certs grew a verdict the API does not send"
    assert "severityFrom" not in js and "severityFor" not in js
    table = js[js.index("const STATUS_CHIP = {"):js.index("};")]
    assert "active: 'ok'" in table and "revoked: 'fail'" in table
    assert "unissued: ''" in table, "an unissued host would be coloured"
    assert "not_after" not in table and "serial" not in table, "an expiry became a verdict"


def test_the_certs_page_asks_before_it_writes_and_offers_nothing_the_api_refuses(
        client) -> None:
    """Every write is confirmed, and no row offers a control its own payload rules out.

    `confirm()` and not the typed `DANGER` word: that gate belongs to commands that cut power,
    and this page has none — the worst outcome here is a host that is not dialled until somebody
    installs a bundle. The guards are the API's, restated: a row outside `HOST_TARGETS` gets no
    buttons at all (`404 {"configured": false}` is all three routes' first line), a never-issued
    host has nothing to revoke and no bundle to download, and the bundle download is a plain
    `GET` link because a session cookie is all a signed `GET` needs.
    """
    js = _code(client.get("/static/page-certs.js").text)
    assert "window.confirm(" in js
    assert "DANGER" not in js, "the power-cut word migrated to a page with no power cut"
    assert "entry.configured" in js and "not in HOST_TARGETS" in js
    assert "entry.status !== 'unissued'" in js, "a row could revoke nothing"
    assert "entry.serial" in js
    assert "bundle.href = '/api/certs/'" in js
    assert "method: 'POST'" in js
    # …and the refusal is text, never markup: these are server sentences
    assert "innerHTML" not in js


def test_the_certs_page_prints_the_restart_sentence_the_api_spoke(client) -> None:
    """`restart_required` prints the route's `hint`, not a sentence the page wrote for itself.

    The restart fact lives in `api.py` (the CA and the client pair are startup material, so the
    table is new before the socket is). A page copy of it is the version that quietly stops
    saying "and every bundle needs re-installing".
    """
    js = client.get("/static/page-certs.js").text
    assert "restart_required" in js
    assert "body.hint" in js
    assert "restart the dashboard" not in js.lower(), "the page invented the restart sentence"


def test_the_password_floor_the_form_checks_is_the_one_the_api_enforces(client) -> None:
    """The client-side length check is a courtesy; the server's is the rule.

    There is no build step to share the constant (a locked anchor), so the two literals are
    pinned together here: a floor raised in `api.py` alone would leave the form promising eight
    characters to a request the server answers `422`.
    """
    js = client.get("/static/page-settings.js").text
    found = re.search(r"const MIN_PASSWORD_LENGTH = (\d+);", js)
    assert found, "page-settings.js no longer names its length floor"
    assert int(found.group(1)) == MIN_PASSWORD_LENGTH


def test_a_rotated_secret_clears_the_cached_session_every_page_uses(client) -> None:
    """`Dash.resetAuth()` is the difference between a password change and a 403 dashboard.

    `POST /api/auth/password` rotates the signing secret on purpose (`auth.update_verifier`),
    which invalidates the CSRF token `ensureAuth()` memoised. Every page writes through
    `fetchJSON`, which reads that cache — so unless the change clears it, the operator changes
    the password, clicks *beeper disable* on `/ups`, and gets `missing or invalid CSRF token`
    until they reload the page. A bounce on a `401` clears it for the same reason: the session it
    described no longer exists.
    """
    app_js = client.get("/static/app.js").text
    assert "function resetAuth(" in app_js
    exports = app_js.rsplit("return {", 1)[1].split("}", 1)[0]
    assert re.search(r"\bresetAuth\b", exports), "Dash.resetAuth is not exported"
    reset = app_js[app_js.index("function resetAuth("):app_js.index("function bounceToLogin(")]
    for field in ("loaded: false", "authenticated: false", "csrf: null"):
        assert field in reset, f"resetAuth() left `{field}` cached"
    assert "authPromise = null" in reset, \
        "resetAuth() left an in-flight status call memoised — the fresh write would reuse it"
    bounce = app_js[app_js.index("function bounceToLogin("):app_js.index("const READ_METHODS")]
    assert "resetAuth()" in bounce, "a 401 bounce kept the dead session's token cached"

    js = client.get("/static/page-settings.js").text
    assert js.count("Dash.resetAuth()") >= 2, \
        "the settings page must reset the cached session after both a change and a sign-out"
    assert "textContent" in js and "innerHTML" not in js, \
        "/settings renders a server sentence as markup"


# ---- the severity language in the static assets --------------------------- #
#
# There is no JS test runner (a locked anchor: adding one would mean a build step).
# What *can* be asserted end-to-end, from the served bytes, is the contract the pages
# depend on: the hero style exists, its colour comes from the shared ok/warn/fail tokens,
# no parallel `.sev-*` vocabulary appeared, and `Dash.hero()` reads the verdict instead of
# comparing the number to a threshold in JavaScript.

ASSETS = ("/static/dash.css", "/static/app.js", "/static/charts.js",
          "/static/page-index.js", "/static/page-disks.js", "/static/page-system.js",
          "/static/page-llm.js", "/static/page-ups.js", "/static/page-login.js",
          "/static/page-settings.js", "/static/page-certs.js")


def _css(client: TestClient) -> str:
    return client.get("/static/dash.css").text


def _css_section(css: str, name: str) -> str:
    """One `/* ---- name … */` section of the stylesheet, up to the **next** section header.

    Slicing to a named neighbour worked while the sheet had five sections. Every page has since
    added a component section, and a slice that runs across someone else's rules accuses the
    fleet block of colouring numbers it never coloured — so the boundary is structural: the end
    of *this* section, whoever comes next.
    """
    start = css.index(f"/* ---- {name}")
    return css[start:css.index("/* ----", start + 10)]


def _hero_css(css: str) -> str:
    """Just the `hero numbers` section of the stylesheet."""
    return css.split("/* ---- hero numbers", 1)[1].split("/* ---- bars", 1)[0]


def test_css_ships_the_hero_number_style(client) -> None:
    css = _css(client)
    hero_block = _hero_css(css)
    for rule in (".hero {", ".hero .label", ".hero .value", ".hero .unit", ".hero .sub",
                 ".hero.ok .value", ".hero.warn .value", ".hero.fail .value",
                 ".hero-bar", ".hero-bar.ok .bar"):
        assert rule in hero_block, f"dash.css lost the {rule} rule"
    # a display size with fixed-width digits, so the number does not jitter between polls
    assert "2.4rem" in hero_block
    assert "tabular-nums" in hero_block


def test_hero_colour_comes_from_the_shared_verdict_tokens(client) -> None:
    """`.hero` reuses `--ok/--warn/--fail`; it does not invent a palette of its own."""
    hero_block = _hero_css(_css(client))
    for token in ("var(--ok)", "var(--warn)", "var(--fail)", "var(--text)",
                  "var(--text-muted)", "var(--text-faint)"):
        assert token in hero_block, f"the hero style no longer uses {token}"


def test_no_stylesheet_rule_uses_an_undeclared_token(client) -> None:
    """A typo'd `var(--x)` renders unstyled and reads as a broken panel, not an error."""
    css = _css(client)
    root = re.search(r":root\s*\{(.*?)\n\}", css, re.S)
    assert root is not None
    declared = set(re.findall(r"(--[a-z0-9-]+)\s*:", root.group(1)))
    used = set(re.findall(r"var\(\s*(--[a-z0-9-]+)", css))
    assert not used - declared


def _code(body: str) -> str:
    """An asset with its comments stripped — prose may *name* a class the code must not define."""
    body = re.sub(r"/\*.*?\*/", " ", body, flags=re.S)
    body = re.sub(r"<!--.*?-->", " ", body, flags=re.S)
    return re.sub(r"^\s*//.*$", " ", body, flags=re.M)


# The `fleet` object paths `/llm`'s aggregate block reads. `engines_total` drives the
# "hidden below two engines" rule and the tag; `engines_live` is what makes a partial sum
# visible; the rest are the row itself.
FLEET_BLOCK_PATHS = frozenset({
    "engines_total", "engines_live", "requests_active", "requests_waiting",
    "prompt_tokens_per_second", "decode_tokens_per_second", "tokens_total",
})
# The summed half of that list — the ones that must be null, not 0, with nothing answering.
FLEET_SUM_PATHS = ("requests_active", "requests_waiting", "prompt_tokens_per_second",
                   "decode_tokens_per_second", "tokens_total")


def _fleet_tag(html: str) -> str:
    """The aggregate block's opening tag — the one place its `hidden` default lives."""
    start = html.index('<section class="card flat fleet"')
    return html[start:html.index(">", start)]


def _fleet_render_path(js: str) -> str:
    """Just the body of `renderFleet()` — the aggregate block's whole code path, comments out.

    Everything the block writes goes through here, so it is the slice that can be asserted
    verdict-free without tripping over the engine panels' rated KV sparkline next door.
    """
    js = _code(js)
    return js[js.index("function renderFleet("):js.index("async function refresh(")]


def _fleet_field_metrics(js: str) -> list[str]:
    """The `fleet` keys the block's rows are bound to, in the order the block prints them."""
    js = _code(js)
    start = js.index("const FLEET_FIELDS = [")
    table = js[start:js.index("];", start) + 2]
    return re.findall(r"metric: '([a-z_]+)'", table)


def test_no_parallel_severity_vocabulary_exists_anywhere(client) -> None:
    """One word per colour: `ok|warn|fail`, as in severity.py and the existing components."""
    for asset in (*ASSETS, *MARKUP_PAGES):
        body = _code(client.get(asset).text)
        assert ".sev-" not in body, f"{asset} invented a .sev-* class"
        assert not re.search(r"classList\.(?:add|toggle)\(\s*[\"'](?:danger|good|warning)[\"']",
                             body), f"{asset} invented a synonym for fail"


def test_app_js_exposes_the_hero_helpers(client) -> None:
    js = client.get("/static/app.js").text
    assert "function hero(" in js
    assert "function severityFrom(" in js
    exports = js.rsplit("return {", 1)[1].split("}", 1)[0]
    for name in ("hero", "severityFrom", "severityFor"):
        assert re.search(rf"\b{name}\b", exports), f"Dash.{name} is not exported"


def test_hero_reads_the_verdict_instead_of_a_threshold(client) -> None:
    """`hero()` may only colour what the API rated — no thresholds re-derived in JS."""
    js = client.get("/static/app.js").text
    start = js.index("function hero(")
    body = js[start:js.index("\n  function setDot", start)]
    assert "severityFrom(" in body
    assert "severityFor(" not in body
    # an unknown value gets n/a and no colour class at all
    assert "naText" in body
    assert re.search(r"raw != null", body)


def test_severity_for_is_kept_as_the_documented_fallback(client) -> None:
    """Every page call site is gone now that phase 05 converted `/ups`.

    `/` was converted in phase 02, `/system` in phase 03, `/llm` in phase 04 and `/ups` in
    phase 05, so no page colours anything from a threshold it wrote itself. The function
    itself stays: it is the documented fallback `setBar()` uses when a caller names no
    verdict, and a page that ever needs a verdict the API does not send should add it to
    `severity.py` rather than here — which is what the docstring on it says.
    """
    js = client.get("/static/app.js").text
    assert "FALLBACK ONLY" in js
    assert "severityFor" in js, "the documented fallback itself was deleted"
    for page in PAGE_SCRIPTS.values():
        assert "severityFor" not in client.get(f"/static/{page}").text, \
            f"{page} colours something from a threshold of its own"


def test_overview_colours_from_the_payload_not_from_js_thresholds(client) -> None:
    """`page-index.js` reads verdicts; it does not compare a number to a bound."""
    js = client.get("/static/page-index.js").text
    assert "severityFrom" in js
    assert "severityFor" not in js


def test_system_page_colours_from_the_payload_not_from_js_thresholds(client) -> None:
    """`page-system.js` hero cards paint payload verdicts, not thresholds of their own.

    Phase 03 task 02's promise: every colour on a host card comes from a `severity` dict
    `severity.py` produced (`cpu.severity.usage_pct`, `memory.severity.used_pct`,
    `disks.severity.worst_used_pct`, `cpu.severity.temp_c`).
    A threshold written here could disagree with the overview's alerts; a hero with no
    verdict prints `n/a` uncoloured, which is `Dash.hero()`'s contract.

    The GPU slot names no verdict on purpose (phase 06): `severity.THRESHOLDS` has no
    `gpu.*` row, the payload carries no `gpus[].severity`, and the hero is built without
    `severity` or `bar` — a bar under a verdictless number would be a verdict by shape.
    """
    js = client.get("/static/page-system.js").text
    assert "severityFor(" not in js, "the system page re-invented a threshold"
    assert "Dash.hero(" in js
    for hook in ("cpu.severity.usage_pct", "memory.severity.used_pct",
                 "disks.severity.worst_used_pct", "cpu.severity.temp_c"):
        assert hook in js, f"the card no longer names {hook} as a colour source"
    # and the GPU hero grades nothing: no verdict hook, no utilisation bar
    assert "gpus[].severity" not in js, "the GPU slot invented a colour source again"
    gpu_slot = js[js.index("function renderGpuSlot("):js.index("function renderGpuExtra(")]
    assert "severity:" not in gpu_slot, "the GPU hero passes a severity option again"
    assert "bar:" not in gpu_slot, "the GPU hero grew a bar back (a verdict by shape)"
    assert "hero-bar" not in gpu_slot, "the GPU hero rebuilt the bar variant of .hero"


#: Every cell of the `/system` GPU card's value grid, in render order, with the `gpus[]`
#: key(s) it prints. This is the `SLOT_FIELDS` device applied to the four values phase 21
#: task 02 created: the table is read out of the served `GPU_VALUE_FIELDS` and resolved
#: against every captured host shape *and* against `/api/system/snapshot`, so a rename on
#: either side fails a test instead of printing `n/a` beside a healthy fleet — and so the
#: dense ` · `-joined sub-line the TODO complained about cannot come back.
GPU_VALUE_CELLS: tuple[tuple[str, tuple[str, ...]], ...] = (
    ("Model", ("model",)),
    ("VRAM", ("vram_used_bytes", "vram_total_bytes")),
    ("Pool", ("mem_used_pct",)),
    ("Temp", ("temp_c",)),
)


def _gpu_value_fields(js: str) -> list[tuple[str, tuple[str, ...]]]:
    """The served `GPU_VALUE_FIELDS` table as `(label, payload keys)` rows."""
    table = re.search(r"const GPU_VALUE_FIELDS = \[(.*?)\n\];", js, re.S)
    assert table, "page-system.js no longer has a GPU_VALUE_FIELDS table"
    rows: list[tuple[str, tuple[str, ...]]] = []
    for entry in re.findall(r"\{[^{}]*\}", table.group(1)):
        label = re.search(r"label: '(\w+)'", entry)
        field = re.search(r"field: '(\w+)'", entry)
        assert label and field, f"a GPU value cell names no label or field: {entry!r}"
        total = re.search(r"total: '(\w+)'", entry)
        rows.append((label.group(1),
                     (field.group(1), total.group(1)) if total else (field.group(1),)))
    return rows


def test_gpu_values_are_four_labelled_cells_not_a_dense_sub_line(client) -> None:
    """`TODO.md:12` — "… is too much info for such small text and should be its own values."

    The GPU slot used to print `Radeon 8060S Graphics · VRAM 180.2 MiB / 512.0 MiB · pool
    79% · 69 °C` as one `.sub` line in 11px mono. It is now four labelled cells, and the
    pin is bidirectional: the table has the four rows in order, and the joined-sentence
    builder that produced the TODO's quoted string is gone (`gpuSub` and its
    `bits.join(' · ')` are the thing that made the card unreadable).

    Two invariants ride on the same slice. The model string is upstream text (a PCI device
    name), so it leaves through `DashCharts.escapeHtml`; and the temperature keeps its
    null guard — `0 °C` would be a cool GPU that does not exist (phase 06).
    """
    js = client.get("/static/page-system.js").text
    assert _gpu_value_fields(js) == list(GPU_VALUE_CELLS), \
        "the GPU value grid is no longer Model / VRAM / Pool / Temp over those payload keys"
    # the °C rides in the value (the label is the word, as on the /disks card and the GPU
    # detail table), and it appears exactly once in the table: one cell, one unit.
    assert js.count("unit: ' °C'") == 1, "the Temp cell's unit is not the one °C on the card"

    body = js[js.index("function gpuValues("):js.index("function renderGpuSlot(")]
    assert "GPU_VALUE_FIELDS.map(" in body, "gpuValues() stopped rendering the table"
    assert "escapeHtml" in body, "the Model cell prints an upstream string unescaped"
    assert "== null" in body, "a cell lost its null guard (missing must print n/a, not 0)"

    # the dense sub-line the TODO quoted is gone, container and all
    assert "function gpuSub(" not in js, "gpuSub() came back"
    assert "join(' · ')" not in js, "the ` · `-joined GPU footnote came back"

    # "More detail" keeps the per-label breakdown: a surface change, not a de-duplication
    extra = js[js.index("function renderGpuExtra("):js.index("function renderHostCard(")]
    assert "Temp" in extra and "gpu.temp_c" in extra, "GPU detail lost its temperature column"


def test_gpu_value_cells_resolve_against_every_captured_host(
        agent_snapshots: dict[str, dict[str, Any]]) -> None:
    """Every key the four cells print exists on every captured card — discrete GPU and APU.

    `tests/card_contract.py` owns the payload table; this resolves the *page's* table
    against the same three captures, which is where a rename would otherwise be caught by
    an operator looking at `n/a` next to a healthy machine. `temp_c` may legitimately be
    `None` (a driver with no hwmon input) — present is the contract, and the cell prints
    `n/a` for it, never `0 °C`.
    """
    for name in HOST_SHAPES:
        payload = parse_host_snapshot(name, agent_snapshots[name], HostCollector(
            RateEstimator(span=60.0)), now=1_000.0).payload
        assert_card_contract(payload)
        for gpu in payload["gpus"]:
            for label, keys in GPU_VALUE_CELLS:
                for key in keys:
                    assert key in gpu, f"{name}: the {label!r} cell has no {key!r} key"
        if not payload["gpus"]:
            # gateway: the omission's input. An empty list is a *fact* about the box, and
            # `renderGpuSlot()` turns that fact into an absent slot rather than an `n/a`.
            assert name == "gateway", "a capture lost its GPU row"


def test_the_gpu_value_cells_are_served_for_the_hosts_that_have_a_card(
        tmp_path: Path, agent_snapshots: dict[str, dict[str, Any]]) -> None:
    """The same four keys over HTTP, on the body `/system` actually renders.

    Parsing in-process proves the source; this proves the endpoint. One app with all three
    hosts injected (dead ports, so no poll can overwrite what the test put there) answers
    with the discrete-GPU card, the APU card, and gateway's empty list — the exact union
    `renderGpuSlot()` branches on: cards present means four labelled values per card, `[]`
    means no slot at all.
    """
    db = str(tmp_path / "gpu-cells.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2,
                              host_targets=tuple(
                                  Target(name, DEAD_URL) for name in HOST_SHAPES)), store)
    test_client = TestClient(app)
    test_client.__enter__()
    try:
        sign_in(test_client)
        hub = app.state.ctx.hub
        for name in HOST_SHAPES:
            hub.jobs[f"host:{name}"].state.payload = parse_host_snapshot(
                name, agent_snapshots[name], HostCollector(RateEstimator(span=60.0)),
                now=1_000.0).payload
        hosts = {row["name"]: row for row in test_client.get("/api/system/snapshot").json()["hosts"]}
        assert set(hosts) == set(HOST_SHAPES)
        for name, row in hosts.items():
            for gpu in row["gpus"]:
                for label, keys in GPU_VALUE_CELLS:
                    for key in keys:
                        assert key in gpu, f"{name}: /api/system/snapshot has no {key!r} " \
                            f"for the {label!r} cell"
        assert hosts["gateway"]["gpus"] == [], \
            "gateway must answer [] — that is what makes the page omit the slot"
        assert hosts["driveripper"]["gpus"] and hosts["deskwork"]["gpus"]
    finally:
        test_client.__exit__(None, None, None)
        store.close()


def test_a_host_with_no_gpu_omits_the_gpu_slot_instead_of_printing_n_a(client) -> None:
    """`TODO.md:12` — "Boxes without a GPU should not report N/A but instead should omit
    these values."

    gateway has no card, and the sixth hero slot used to say so with a big faint `n/a` plus
    the sentence "No GPU reported by this agent" — invariant 3's complaint in the one place
    the page had not learned it. `renderGpuSlot()` now empties the slot and sets `hidden`,
    and `[hidden] { display: none !important }` at the end of `dash.css` is what takes the
    wrapper out of the `.heroes` grid so the row reflows to five. Pinned on the served
    bytes (no JS runner — a locked anchor) and measured in a browser by
    `data/logs/21-task02-gpu-values.cjs`.

    The wrapper element itself stays in `hostCard()`: the hero row remains one static list
    of six `data-k` slots (pinned by the test below), a host whose agent starts reporting a
    card has something to grow into, and an empty hidden element is zero footprint.
    """
    js = client.get("/static/page-system.js").text
    slot = js[js.index("function renderGpuSlot("):js.index("function renderGpuExtra(")]
    assert "cell.hidden = gpus.length === 0" in slot, \
        "the GPU slot no longer hides itself when the host has no card"
    assert "No GPU reported" not in js, "the no-GPU n/a sentence came back"
    assert "n/a" not in slot, "the GPU slot grew its own n/a fallback again"
    # and the row itself keeps the six static slots, so a GPU host still has somewhere to go
    assert "display: none !important" in client.get("/static/dash.css").text, \
        "[hidden] stopped beating .hero-slot's display, so a hidden slot would still " \
        "occupy a hero track"


def test_gpu_value_grid_ships_no_verdict_and_wraps(client) -> None:
    """The four new cells colour nothing and let a long model string wrap.

    Phase 06's rule extends to them: `severity.THRESHOLDS` has no `gpu.*` row, the payload
    carries no `gpus[].severity`, so neither the markup nor the grid may reach for
    `--ok`/`--warn`/`--fail` or a `severity` option (a busy GPU on an LLM server is the job).
    `overflow-wrap` is the other half of `TODO.md:12` — the readability complaint *is* the
    20-character model string, and truncating it would keep the complaint.
    """
    js = client.get("/static/page-system.js").text
    # word-boundary on purpose: the docstring in this slice is allowed to *say* "severity",
    # the code is not allowed to pass one (or a bar, or a verdict class) to anything
    markup = js[js.index("const GPU_VALUE_FIELDS"):js.index("function renderGpuSlot(")]
    verdicts = re.findall(r"\b(ok|warn|fail|severity:|bar:|hero-bar)\b", markup)
    assert not verdicts, f"the GPU value grid grew a verdict: {verdicts}"

    css = client.get("/static/dash.css").text
    rule = re.search(r"\.gpu-values \{([^}]*)\}", css)
    assert rule, "/system lost its .gpu-values grid"
    assert "auto-fit" in rule.group(1), ".gpu-values stopped adapting to the hero track"
    wrap = re.search(r"\.gpu-values \.value \{([^}]*)\}", css)
    assert wrap and "overflow-wrap" in wrap.group(1), \
        "a long GPU model string truncates instead of wrapping"
    for token in ("--ok", "--warn", "--fail"):
        assert token not in rule.group(1) + (wrap.group(1) if wrap else ""), \
            f"the GPU value grid coloured itself with {token} (severity.py rates no GPU)"


def test_system_host_card_is_six_heroes_without_per_core(client) -> None:
    """Each host card ships six hero slots in order: CPU, MEM, TEMP, DISK, GPU, NET.

    Asserted on the served script because there is no JS test runner (a locked anchor).
    The two dense `.metrics` rows and the per-core heat bars are exactly what made the
    card unreadable, and "no per-core anywhere on /system" is a promise a stray
    `renderCores` call would silently break — the series stays stored, the page just
    stopped drawing it (PLAN.md *Dropped visuals*).

    Six **slots**, not six visible heroes: the GPU slot ships `hidden` and
    `renderGpuSlot()` un-hides it only for a host whose payload has a card, so gateway's
    card renders five (pinned by the test above and measured in the browser by
    `data/logs/21-task02-gpu-values.cjs`). The static order below is what makes that a
    one-line rule instead of a re-flowing template.
    """
    js = client.get("/static/page-system.js").text
    card = js[js.index("function hostCard("):js.index("function renderHostCard(")]
    slots = re.findall(r'<div class="(?:hero|hero-slot)[^"]*" data-k="([^"]+)"', card)
    assert slots == ["cpu", "mem", "temp", "disk", "gpus", "net"], \
        "the hero row is no longer the six numbers in the agreed order"
    assert re.search(r'data-k="gpus"[^>]*hidden', card), \
        "the GPU slot is visible before the payload says this host has a card"
    # per-core visualisation is gone from the card code entirely
    assert "cores" not in card, "a per-core visual came back to the card"
    assert "renderCores" not in js and "core_usage" not in js
    # the NET slot is a slot with two lines and no verdict: a byte rate has no good/bad
    assert 'data-k="net"' in card
    assert not re.search(r'data-k="net"[^>]*data-sev', card), "the NET slot invented a colour"
    # what the glance leaves out stays reachable, collapsed by default
    assert "More detail" in card
    for key in ("load", "freq", "dr", "dw", "dutil", "uptime", "details"):
        assert f'data-k="{key}"' in card, f"{key} left the page instead of the glance"
    # the panel owns its charts: the slots live inside the card, not on the page
    for chart in ("util", "net"):
        assert f'data-chart="{chart}"' in card, f"the panel lost its {chart} chart slot"


def test_system_page_keeps_no_fleet_wide_chart_or_metric_picker(client) -> None:
    """Nothing on `/system` plots two hosts, and nothing needs a selection to make sense.

    TODO.md L4 is the instruction ("The system page doesn't need shared charts for
    anything") and the overview's alerts + fleet table are what made removing them safe
    (phase 02). Asserted on the served bytes because the only thing that would otherwise
    notice a resurrected `<select>` is a browser: there is no JS test runner (a locked
    anchor), and `test_no_page_carries_an_id_nothing_reads` cannot see ids that were deleted
    correctly from the page but are still queried by the script.
    """
    html = _code(client.get("/system").text)
    for gone in ('id="chart-cpu"', 'id="chart-mem"', 'id="chart-disk"', 'id="chart-net"',
                 'id="chart-gpu"', 'id="chart-temp"', 'id="chart-detail"', 'id="detail-host"',
                 'id="detail-metric"', 'id="f-cpu"', 'id="f-load"', 'id="f-gpu"',
                 "Fleet totals", "Fleet charts", "Series detail", "<select"):
        assert gone not in html, f"/system still carries {gone}"
    # the two panels that are left are the per-host grid and the event feed
    assert html.count("<section") == 2, "/system grew a panel back on top of the host grid"
    assert 'id="hosts"' in html and 'id="events"' in html

    # and the script must not reach for the deleted endpoints/ids either — a `#detail-host`
    # query against a removed node is a silent null, so the picker would just never appear
    js = client.get("/static/page-system.js").text
    for gone in ("#chart-", "detail-host", "detail-metric", "detail-note",
                 "renderFleet", "makeCharts", "refreshGpuChart", "populateDetailMetrics"):
        assert gone not in js, f"page-system.js still references {gone}"


def test_every_system_chart_is_drawn_inside_its_own_host_panel(client) -> None:
    """One host per chart: the legends of `/system` can never list two machine names.

    The construction is a factory that takes the card, so a chart cannot be built against a
    page-level id; the metric list is per host, so the GPU streams cannot leak from one
    panel into another; and a panel is torn down (with its charts) when its host leaves the
    payload, which is the bug class a keyed-by-host chart map exists to avoid.
    """
    js = client.get("/static/page-system.js").text
    builds = re.findall(r"new DashCharts\.LineChart\(([^,]+),", js)
    assert builds, "the system page builds no charts at all"
    # every chart is built from a `[data-chart]` slot inside the host card, never from a
    # page-level id — which is what makes "one host per chart" structural, not a convention
    assert all(re.search(r"(?:card|slot)\.querySelector\(.\[data-chart=", b) for b in builds), \
        f"a chart is built outside a host panel: {builds}"
    # three construction sites, one per slot (util, net, gpu) — never one per metric
    assert len(builds) == 3, f"charts are not built one per panel slot: {builds}"
    assert sorted(re.findall(r'data-chart=\\?"(\w+)"', " ".join(builds))) == ["gpu", "net", "util"]

    factory = js[js.index("async function renderHostCharts("):js.index("function pruneHosts(")]
    assert "hosts=${encodeURIComponent(host.name)}" in factory, \
        "the per-host chart query is not scoped to one host"
    assert "&metrics=" in factory and "state.range" in factory, \
        "a host's charts need one metric list and the selected window"
    # GPU series are named from the payload's own `gpus[].index`, never discovered/guessed
    assert "gpu.busy_pct@" in js and "gpu.index" in js
    # the GPU chart exists only while the host reports cards
    gpu_slot = js[js.index("function hostChartSet("):js.index("function seriesFor(")]
    assert re.search(r"if \(!wantsGpu && set\.gpu\)", gpu_slot), \
        "a host that stops reporting GPUs keeps a GPU chart it has no data for"

    pruner = js[js.index("function pruneHosts("):js.index("// ---- snapshot")]
    assert "state.hosts.delete(name)" in pruner and "state.charts.delete(name)" in pruner, \
        "a host that left the payload keeps a live panel and drawing charts"


def test_system_history_charts_are_collapsed_behind_a_toggle(client) -> None:
    """TODO.md L4: "The historical charts on the system resources page should only be visible
    if expanded. I only want to see current stats to keep things clean."

    The default `/system` view is the hero row. Pinned on the served script because the card
    markup is generated in JS and there is no JS test runner (a locked anchor), and the two
    ways this regresses are invisible otherwise: a `<details open>` (charts visible by
    default, i.e. the task un-done but the page still pretty) and a paint pass that runs
    while the stack is shut, which builds three `LineChart`s per host inside a
    `display:none` container — measured 0 px wide, never drawn, and rebuilt every poll.
    """
    js = client.get("/static/page-system.js").text
    card = js[js.index("function hostCard("):js.index("function memorySub(")]

    # the stack is *wrapped*, not merely preceded by a heading: it lives inside the <details>
    box = card.index('<details class="charts-box" data-k="charts">')
    stack = card.index('<div class="host-charts">')
    closed = card.index("</details>")
    assert box < stack < closed, "the chart stack is not inside the toggle"
    assert closed < card.index("More detail"), "the charts toggle swallowed the detail row too"
    assert not re.search(r"<details[^>]*\bopen\b", card), \
        "a panel ships its charts open — the default view is not current stats"
    assert re.search(r"<summary[^>]*>\s*Charts", card), "the toggle no longer reads Charts"
    # it also says which window the expanded stack draws (the chips stay in the page head)
    assert 'data-k="charts-window"' in card, "the toggle does not carry the window"
    # …and the toggle is what turns the paint pass on
    assert "addEventListener('toggle'" in card and "chartsToggled(" in card

    setter = js[js.index("function setChartsWindow("):js.index("function memorySub(")]
    assert "state.rangeKey" in setter, \
        "the toggle re-derives its window label instead of using the chips' own"
    handler = js[js.index("Dash.rangeControl("):js.index("state.poller = poll(")]
    assert "state.rangeKey = key" in handler and "setChartsWindow(" in handler, \
        "changing the window leaves every toggle labelling the old one"

    # nothing is built or drawn while the stack is shut, in either path that could paint
    paint = js[js.index("function drawHostCharts("):js.index("async function renderHostCharts(")]
    assert "if (!chartsOpen(card)) return" in paint, "a closed panel gets painted anyway"
    assert "hostChartSet(card, host)" in paint, \
        "the LineChart instances are no longer built by the open pass"
    toggle = js[js.index("function chartsToggled("):js.index("function drawHostCharts(")]
    assert "if (!chartsOpen(card)) return" in toggle, "closing the stack still paints"
    assert "renderHostCharts(card, host)" in toggle and "state.range" in toggle, \
        "a cached response from another window is drawn under this window's label"

    # the request discipline is unchanged: one per host per refresh, every series named
    fetch = js[js.index("async function renderHostCharts("):js.index("function windowLabel(")]
    assert "hostChartSet(" not in fetch, "the poll path still builds charts for closed panels"
    assert "state.history.set(" in fetch, \
        "the response is not kept, so the first open is an empty box until the next poll"
    assert "if (range === state.range) drawHostCharts(" in fetch, \
        "a response for a window the operator just left is painted under the new label"
    assert "drawHostCharts(" in fetch, "an open panel is no longer repainted on refresh"


def test_a_pruned_host_takes_its_charts_toggle_with_it(client) -> None:
    """A host that leaves the payload must leave no orphan control in the grid.

    The toggle is a child of the panel, which is why `card.remove()` is enough — but that is
    only true while the markup is built inside `hostCard()`, so the placement is pinned here
    along with the three per-host Maps the panel owns.
    """
    js = client.get("/static/page-system.js").text
    card = js[js.index("function hostCard("):js.index("function memorySub(")]
    assert 'data-k="charts"' in card, "the toggle is no longer part of the panel"
    pruner = js[js.index("function pruneHosts("):js.index("// ---- snapshot")]
    assert "state.hosts.get(name).remove()" in pruner
    for owned in ("state.charts", "state.payloads", "state.history"):
        assert f"{owned}.delete(name)" in pruner, f"{owned} outlives the panel it belongs to"


def test_the_charts_toggle_is_a_quiet_disclosure_not_a_new_component(client) -> None:
    """The collapse adds no palette and no second vocabulary (UI conventions).

    Open/closed is carried by a caret *shape* as well as a colour step, the summary is muted
    rather than accented, and it introduces no `.sev-*` family — the same rule the hero
    numbers live by, checked here because a `<summary>` is the first control on the page a
    designer might be tempted to grade.
    """
    css = client.get("/static/dash.css").text
    block = css[css.index("details.charts-box { "):css.index(".host-charts {")]
    assert "details.charts-box > summary::before" in block, "the toggle has no caret shape"
    assert 'details.charts-box[open] > summary::before' in block, \
        "open and closed differ only in colour"
    assert "var(--text-faint)" in block, "the closed toggle is not muted"
    assert ".sev-" not in block and "var(--accent)" not in block, "the toggle invented a palette"
    assert 'class="charts-box"' in client.get("/static/page-system.js").text, \
        "the stylesheet styles a class the page no longer renders"


def test_an_expanded_chart_stack_does_not_grow_its_collapsed_siblings(client) -> None:
    """One host open must not stretch the hosts beside it into blank cards.

    `/system` is the same shape `/llm` had to fix: an expanded panel beside a collapsed one
    grows the collapsed card to match, and a blank panel reads as "no data" (the misreading
    the unconfigured rules exist to prevent). `.grid.items-start` already exists for exactly
    this, so the page uses it rather than growing a rule of its own.
    """
    html = _code(client.get("/system").text)
    hosts_class = re.findall(r'<div class="([^"]*)" id="hosts">', html)
    assert hosts_class == ["grid auto items-start"], \
        f"the host grid stretches its cards again: {hosts_class}"
    assert ".grid.items-start" in client.get("/static/dash.css").text, \
        "the rule the host grid relies on is gone"


def test_every_system_chart_names_itself_for_assistive_tech(client) -> None:
    """A 120px SVG is silence to a screen reader unless the page names it.

    The phase-03 accessibility pass (task 04) found the per-host charts drawing anonymous
    plots: the legend is a sibling element and labels nothing, so the `<svg>` itself must
    carry `role="img"` + `aria-label` that says which host and which metrics. Pinned on the
    served bytes because there is no JS test runner (a locked anchor).
    """
    charts_js = client.get("/static/charts.js").text
    # the shared LineChart applies the name to the svg, and only when the caller opted in
    assert "if (this.opts.ariaLabel)" in charts_js, "LineChart stopped honouring ariaLabel"
    assert "setAttribute('role', 'img')" in charts_js
    assert "setAttribute('aria-label', String(this.opts.ariaLabel))" in charts_js

    js = client.get("/static/page-system.js").text
    # all three slots name themselves, and each name starts with the host the panel belongs
    # to — an aria-label that cannot say *which machine* is not an accessible name here
    assert js.count("ariaLabel: `") == 3, "a per-host chart slot lost its accessible name"
    for slot in ("utilisation", "network traffic", "GPU busy"):
        assert f"${{host.name}} \u2014 {slot}" in js or f"${{host.name}} — {slot}" in js, \
            f"the {slot} chart has no host-scoped accessible name"


# ---- event feeds: a bounded, paginated window ----------------------------- #
#
# Every `ul.events` feed is one component (`Dash.eventsPager`) because a pager that
# works on only one page is the bug this shape prevents: the `event` table grows for as long
# as the fleet runs, and an unbounded feed turns `/system` into a scroll to nowhere
# (`TODO.md` L6 — "All the events tables need to be scrollable and paginated"). There is no
# JS test runner (a locked anchor), so what is pinned here is the shape every feed must keep:
# one shared renderer, a fetch bigger than one page, a footer that counts and labels itself,
# and a container that scrolls instead of growing the page.

# page -> (its script, the `source=` the poller stores that page's events under)
EVENT_FEEDS = {
    "/system": ("page-system.js", "system"),
    "/disks": ("page-disks.js", "disks"),
    "/llm": ("page-llm.js", "llm"),
    "/ups": ("page-ups.js", "ups"),
}


def _event_feed_path(js: str) -> str:
    """Just the `refreshEvents()` half of a page script — the feed's whole code path, comments out."""
    js = _code(js)
    return js[js.index("async function refreshEvents("):]


def _pager_call(feed: str, selector: str) -> str:
    """The options object of one `Dash.eventsPager($('<selector>'), …)` call inside the feed path.

    Sliced per list so an assertion can name *which* feed lost its renderer, its accessible name
    or its empty sentence. `/ups` is the page with two of them, so a whole-file assertion there
    cannot tell one list from the other.
    """
    head = f"Dash.eventsPager($('{selector}')"
    assert head in feed, f"this feed is no longer rendered through Dash.eventsPager ({selector})"
    start = feed.index(head)
    end = feed.find("});", start)
    assert end != -1, f"the {selector} pager call is never closed"
    return feed[start:end]


def _feed_fetch_url(js: str) -> str:
    """The `/api/events` URL a feed asks for, quoted or templated."""
    found = re.search(r"fetchJSON\([`'](/api/events[^`']*)[`']\)", _event_feed_path(js))
    assert found, "this page no longer fetches the event feed"
    return found.group(1)


def test_the_event_feeds_are_one_shared_pager_not_one_per_page(client) -> None:
    """`Dash.eventsPager()` renders every feed, and no page grows its own pager.

    One copy per page is one chance per page to keep the old behaviour — and `/system` is the
    one whose feed was already too tall when this was written down. `/disks` joined as a
    fourth call site of the same helper, not as a fifth implementation of it.
    """
    app_js = _code(client.get("/static/app.js").text)
    assert app_js.count("function eventsPager(") == 1
    exports = client.get("/static/app.js").text.rsplit("return {", 1)[1].split("}", 1)[0]
    assert "eventsPager" in exports, "Dash.eventsPager is not exported"

    for path, (script, _) in EVENT_FEEDS.items():
        js = _code(client.get(f"/static/{script}").text)
        assert "Dash.eventsPager($('#events')" in js, f"{path} does not render its feed through the pager"
        assert "function eventsPager(" not in js, f"{path} invented its own pager"
        assert "events.slice(" not in js, f"{path} windows its own events instead of asking the pager"
        assert "row:" in _event_feed_path(js), f"{path} passes no row renderer"


def test_the_pager_pages_50_events_and_fetches_more_than_one_page(client) -> None:
    """The two numbers that make a client-side pager work, and the relation between them.

    `EVENT_PAGE_SIZE` is the 50 the operator asked for; `EVENT_FEED_LIMIT` is what the feed
    asks `/api/events` for. A limit at or below the page size is a pager that silently never
    shows — there is never a second page to reach — and the feeds used to fetch 20/25/40.
    """
    app_js = client.get("/static/app.js").text
    page_size = re.search(r"const EVENT_PAGE_SIZE = (\d+);", app_js)
    feed_limit = re.search(r"const EVENT_FEED_LIMIT = (\d+);", app_js)
    assert page_size and int(page_size.group(1)) == 50, "a feed no longer pages 50 events"
    assert feed_limit, "the feeds' event limit is no longer a named constant"
    assert int(feed_limit.group(1)) > int(page_size.group(1)), \
        "a fetch at or below one page means page 2 can never exist"

    for path, (script, source) in EVENT_FEEDS.items():
        url = _feed_fetch_url(client.get(f"/static/{script}").text)
        assert "EVENT_FEED_LIMIT" in url, f"{path} hardcodes its own event limit"
        assert f"source={source}" in url, f"{path} asks for the wrong event source"


def test_the_pager_footer_counts_and_labels_its_controls(client) -> None:
    """The footer counts (`1\u201350 of 137`), and prev/next are labelled and disabled at the ends.

    The count is what tells the operator the window is a window; a control that stays live at
    the last page claims there is more history than there is.
    """
    app_js = _code(client.get("/static/app.js").text)
    assert "${first}\u2013${last} of ${total}" in app_js, "the footer no longer counts"
    assert 'data-pager="prev"' in app_js and 'data-pager="next"' in app_js
    assert "prev.setAttribute('aria-label'" in app_js
    assert "next.setAttribute('aria-label'" in app_js
    assert "prev.disabled = pager.page === 0" in app_js
    assert "next.disabled = pager.page >= pager.pages - 1" in app_js
    # pagination only applies when there is more than one page of data
    assert "foot.hidden = !paginating" in app_js

    css = client.get("/static/dash.css").text
    assert ".events-pager {" in css, "the pager footer has no style"
    assert "button.ghost:disabled" in css, "a disabled pager control looks live"


def test_the_event_feeds_scroll_instead_of_growing_the_page(client) -> None:
    """The `<ul>` is the scrollable element, bounded in `dash.css`; the page stays short.

    Pinned on the served bytes because there is no JS test runner (a locked anchor): a
    stylesheet edit that drops `max-height` is invisible until the feed is long, and by then
    the page is massive again.
    """
    css = client.get("/static/dash.css").text
    block = css[css.index("ul.events {"):css.index("}", css.index("ul.events {"))]
    assert "max-height" in block and "overflow-y: auto" in block, \
        "the event feed is unbounded again — the page grows with history"

    for path in EVENT_FEEDS:
        html = client.get(path).text
        assert '<ul class="events" id="events"' in html, f"{path} lost its feed's id"


def _details_blocks(html: str) -> list[str]:
    """Every `<details>…</details>` block on a served page, in document order.

    Nesting is not a thing on these pages (one disclosure per card), so a flat scan of pairs is
    enough — and it is what lets a pin say *no disclosure contains this*, rather than only
    "not the one disclosure I happen to know about". Phase 26 needs exactly that: the operator's
    complaint was that a connection error was reachable only by opening something.
    """
    blocks = []
    for found in re.finditer(r"<details\b[^>]*>", html):
        end = html.find("</details>", found.end())
        assert end != -1, "a served <details> is never closed"
        blocks.append(html[found.start():end])
    return blocks


def test_ups_power_events_feed_sits_behind_a_collapsed_disclosure(client) -> None:
    """The `/ups` power feed is *expandable*: one `details.events-box`, shut by default.

    `TODO.md:4` asked for an expandable list of incidents and phase 26 kept that shape — what it
    overruled was *what* was behind it. A collapsed `<details>` renders no content, so the shut
    card is still the resting state; since phase 26 it gates **visibility only** (the feed is
    fetched on every poll, which the next test pins), and it holds only the power kinds.

    Pinned on the served bytes because there is no JS test runner (a locked anchor): an `open`
    attribute would undo the phase silently, the `#events` id has to stay *inside* the disclosure
    or the pager and the bounded 320px scroll lose their target, and the **error** half
    (`#events-errors`) has to be outside *every* disclosure and ship `hidden` rather than open —
    a `NUT server NutError: cannot reach upsd …` line an operator has to click to read is the
    bug this phase exists to fix (`TODO.md:6`).
    """
    html = _code(client.get("/ups").text)
    box = re.search(r'<details class="events-box">(.*?)</details>', html, re.S)
    assert box, "the Power events card is no longer a details.events-box disclosure"
    assert not re.search(r"<details[^>]*\bopen\b", html), \
        "the disclosure ships open — the list is tall again, not expandable"
    inner = box.group(1)
    assert "<summary>Power events</summary>" in inner, "the summary lost its label"
    assert '<ul class="events" id="events"' in inner, "the feed moved outside the disclosure"
    assert "loading…" in inner, "the first-expand placeholder is gone"
    assert "<h3>Power events</h3>" not in html, "the card heads its own body twice"

    # The error half is on the page **and not collapsible**: no disclosure anywhere holds it.
    # The card-local pin in `test_the_ups_connection_errors_are_a_card_of_their_own_above_the_disclosure`
    # checks the card does not *contain* a `<details>`; this is the stronger direction — moving
    # that card inside a new disclosure somewhere else would pass there and fail here.
    assert 'id="events-errors"' in html, "the connection-error list left the served page"
    assert not any('id="events-errors"' in block for block in _details_blocks(html)), \
        "the error list is inside a disclosure — reading it needs a click again"
    card_open = html[html.index('<section class="card" id="ups-errors-card"'):
                     html.index(">", html.index('<section class="card" id="ups-errors-card"'))]
    assert "hidden" in card_open, \
        "the error card's resting state is visible — an empty card on every quiet day"

    # the rest of the page is untouched by the disclosure
    for still_there in ('id="ups-cards"', 'id="chart-charge"', 'id="chart-load"',
                        'id="confirm-dialog"'):
        assert still_there in client.get("/ups").text, f"/ups lost {still_there}"


# The event kinds `/ups` keeps behind the collapsed disclosure, and the writers that store
# them. `collectors.py` writes `status` (an `ups.status` transition, power loss included)
# and `test` (a self-test verdict); `api.py` writes `action` (a command this page sent).
# Everything else in the feed is a connection/error event (`unreachable` / `reachable` /
# `recording` / `store-error`) and belongs in the list that is never hidden.
UPS_POWER_EVENT_KINDS = ("status", "test", "action")


def _power_event_kinds(js: str) -> frozenset[str]:
    """The kinds `page-ups.js` keeps behind the disclosure, read out of its own set literal.

    Parsing beats matching one exact line. The claim is *these three and only these* — a kind
    added to the hidden list moves an operator-visible row out of sight, and a kind dropped from
    it hides a power event — so an exact-string assert that happens to survive a reformat is not
    the pin. An empty set is refused rather than returned, because it would make every event an
    error row and look like a passing classification.
    """
    found = re.search(r"const POWER_EVENT_KINDS = new Set\(\[(.*?)]\)", js, re.S)
    assert found, "page-ups.js no longer defines POWER_EVENT_KINDS as a set literal of kind words"
    kinds = re.findall(r"['\"]([^'\"]+)['\"]", found.group(1))
    assert kinds, "POWER_EVENT_KINDS is empty — every event would land in the error list"
    return frozenset(kinds)


def test_ups_events_are_fetched_on_every_poll(client) -> None:
    """Phase 19's lazy gate is out, and the feed splits into power events and errors.

    `TODO.md:6` is not a complaint about the disclosure existing, it is a complaint about what
    was behind it: a poll failure (`NUT server NutError: cannot reach upsd … (timed out after
    4s)`) sat in the same collapsed list as the power events, so the one thing an operator
    needs without opening anything was the one thing they had to open something for. The fix
    is page-side and keyed on the stored `kind`: `status` / `test` / `action` stay behind the
    disclosure, **everything else** is the always-visible error list — and because that list
    is visible, `refresh()` fetches on every poll (a visible list that ages is worse than one
    more 200-event fetch per interval). `/api/events` grew no vocabulary for any of this.

    Pinned on the served script because there is no JS test runner (a locked anchor), and
    pinned in both directions: the gate's absence *and* the kind set, so a silent rename on
    the writer's side fails here instead of moving errors back into the hidden list.
    """
    js = _code(client.get("/static/page-ups.js").text)

    # The kind set, read out of the literal instead of matched as one line: exactly these three.
    assert _power_event_kinds(js) == frozenset(UPS_POWER_EVENT_KINDS), \
        (f"the hidden list's kind set is {sorted(_power_event_kinds(js))}, not "
         f"{sorted(UPS_POWER_EVENT_KINDS)} — that classification is the operator's, not the page's")

    # The lazy cache is gone: with an always-visible list there is nothing left to stamp.
    decl = js[js.index("const state = {"):js.index("const MARKS")]
    assert "events" not in decl, "the disclosure's lazy-fetch state came back"
    assert "state.events" not in js, "something still reads the deleted state.events object"

    # The poll path asks every interval, gated on nothing.
    refresh = js[js.index("async function refresh("):js.index("async function refreshEvents(")]
    assert re.search(r"^\s*await refreshEvents\(\);", refresh, flags=re.M), \
        "the poll loop no longer fetches the feed on every poll"
    assert "state.events.open" not in refresh and "eventsBox" not in refresh, \
        "the fetch is gated on the disclosure again"

    # The toggle handler's fetch logic is gone with it: the native `<details>` now gates only
    # visibility, so no `toggle` listener may exist to decide whether to fetch.
    boot = js[js.index("document.addEventListener('DOMContentLoaded'"):]
    assert "addEventListener('toggle'" not in boot, \
        "a toggle handler is deciding whether to fetch again"
    assert "eventsBox" not in boot, "the disclosure's fetch-on-expand handler came back"

    # One fetch, two lists, split on `kind` — and the URL is the phase-19 one verbatim.
    feed = _event_feed_path(js)
    assert _feed_fetch_url(js) == "/api/events?limit=${Dash.EVENT_FEED_LIMIT}&source=ups", \
        "the feed's fetch is no longer the unchanged /api/events call"
    for vocabulary in ("kind=", "page=", "severity="):
        assert vocabulary not in _feed_fetch_url(js), \
            f"/api/events grew {vocabulary[:-1]} vocabulary for a page-side split"
    assert "const power = data.events.filter((e) => POWER_EVENT_KINDS.has(e.kind));" in feed, \
        "the power list is no longer the filter's positive arm"
    assert "const errors = data.events.filter((e) => !POWER_EVENT_KINDS.has(e.kind));" in feed, \
        "the error list is no longer the filter's default arm (an unknown kind must be visible)"

    # Stale-last-good: the catch clause does *nothing*, so a poll that never answered leaves
    # both `<ul>`s holding the rows they already had (the pager rewrites a list only when its
    # markup changed — invariant 4's shape on the page side).
    opened = "} catch (err) {"
    at = feed.index(opened)
    catch_body = feed[at + len(opened):feed.index("}", at + len(opened))].strip()
    assert catch_body == "", \
        f"the failure path does something ({catch_body!r}) instead of leaving the last good rows"


def test_the_ups_event_rows_keep_the_date_time_and_severity_shape(client) -> None:
    """`TODO.md:4`'s other half: an expandable list is only *clear* if each row says when.

    Phase 19's disclosure and phase 26's split are the new parts; this is the half that had to
    survive both untouched. Every row still opens with a `<time>` carrying a month/day plus a
    24-hour clock, then the UPS name inside the `sev <severity>` chip the stylesheet colours from
    the payload's own verdict, then the message through `eventText()` (subject named once) with
    the runtime footnote only when the event actually carries one. Pinned on the served script
    because there is no JS test runner (a locked anchor): a "tidy-up" of the row template that
    drops the timestamp, prints the raw message, or escapes nothing would ship silently.

    Since phase 26 task 02 the renderer is **one const read by both lists**, so the two halves
    of one feed cannot grow two shapes — which is what this reads, rather than a `row:` option
    that could differ per list.
    """
    js = _code(client.get("/static/page-ups.js").text)
    feed = _event_feed_path(js)
    at = js.index("const eventRow = (event) =>")
    row = js[at:js.index("async function refreshEvents(", at)]

    # the date/time: `<time>` first, month + day + hour + minute, 24-hour (the operator reads
    # an incident log in the order it happened, and "14:05" on its own is not that)
    assert "<time>" in row and "</time>" in row, "the row lost its timestamp element"
    assert "new Date(event.ts * 1000).toLocaleString(" in row, \
        "the row formats something other than the event's own timestamp"
    for option in ("month: 'short'", "day: 'numeric'", "hour: '2-digit'", "minute: '2-digit'",
                   "hour12: false"):
        assert option in row, f"the timestamp no longer asks for {option}"
    assert row.index("<time>") < row.index('class="sev'), "the row no longer leads with the date"

    # who: the host inside the verdict chip, escaped, and the severity is the API's word
    assert 'class="sev ${event.severity}"' in row, \
        "the row stopped taking its colour word from the stored severity"
    assert "${DashCharts.escapeHtml(event.host)}</span>" in row, \
        "the row no longer names the UPS it belongs to, escaped"

    # what: the message through the shared subject-said-once cleaner, and escaped
    assert "${DashCharts.escapeHtml(eventText(event))}" in row, \
        "the message is no longer cleaned and escaped (raw HTML from an upstream is a bug)"

    # the runtime footnote is conditional: an event with no runtime says nothing about one
    assert "event.data && event.data.runtime_seconds" in row, \
        "the runtime footnote is no longer gated on the event carrying a runtime"
    assert "duration(event.data.runtime_seconds)} runtime)" in row, \
        "the runtime footnote stopped printing the stored seconds as a duration"

    # and the renderer is still handed to the shared pager over the bounded list, labelled.
    # Per **call**, not per file: `#events-errors` is a list of its own now, and the claim is
    # that it is drawn, named and emptied exactly like the power list — a count of `row:` in the
    # file would still pass if one call lost its renderer to a default.
    for selector, label, empty in (("#events", "Power events", "No power events yet"),
                                   ("#events-errors", "Connection & errors",
                                    "No connection errors")):
        call = _pager_call(feed, selector)
        assert "row: eventRow," in call, f"the {selector} list is no longer drawn by the shared row"
        assert f"label: '{label}'" in call, f"the {selector} list lost its accessible name"
        assert empty in call, f"the {selector} list no longer says which feed is empty"

    # one renderer, two lists: a template the two lists do not share would be two shapes for one
    # event, and the row may not branch on which list it landed in — the only split is the kind set
    assert js.count("const eventRow = (event) =>") == 1, \
        "the /ups lists no longer share one row template"
    assert "event.kind" not in row and "POWER_EVENT_KINDS" not in row, \
        "the row template reads the kind — the two lists are growing two shapes"

    # The card's visibility is the one state this page claims about a list it cannot see, it is
    # decided by the **error** half alone, and only after both lists are painted (earlier would
    # flash the `loading…` seed on a first fetch with no error rows). The markup's own `hidden`
    # default is pinned in test_ups_power_events_feed_sits_behind_a_collapsed_disclosure.
    hidden_at = feed.index("$('#ups-errors-card').hidden")
    assert feed[:hidden_at].count("Dash.eventsPager(") == 2, \
        "the card's visibility is decided before both lists are drawn"
    assert feed[hidden_at:feed.index(";", hidden_at)].endswith("= errors.length === 0"), \
        "the error card's visibility no longer follows the error half of the feed"


def test_the_ups_connection_errors_are_a_card_of_their_own_above_the_disclosure(client) -> None:
    """Phase 26 task 02: the error half of the feed is a card, not a second list in a `<details>`.

    `TODO.md:6` is that a `NUT server NutError: cannot reach upsd …` line is not something to
    open a summary for. So the error rows get their own `section.card` **above** the Power
    events disclosure, built from the vocabulary every other card on this page uses
    (`.card > header`, `.card > .body`, `ul.events`, the pager's strip) — **no new stylesheet
    selector**, because a second style for a second list is a second thing to keep in sync with
    the bounded 320px scroll and the `1\u201350 of N` footer.

    `hidden` is the resting state in the markup and the script keeps it true while the feed has
    no non-power kinds: a permanent empty "Connection & errors" card is exactly the ink the
    page's empty-state rules exist to avoid, and the first `unreachable` row is what shows it.
    """
    html = _code(client.get("/ups").text)

    card_at = html.index('<section class="card" id="ups-errors-card"')
    card_end = html.index("</section>", card_at)
    card = html[card_at:card_end]
    opening = html[card_at:html.index(">", card_at)]
    assert "hidden" in opening, "the error card ships visible with nothing in it"
    assert '<ul class="events" id="events-errors"' in card, "the error card has no bounded feed"
    assert "<h3>Connection &amp; errors</h3>" in card, "the card lost its title"
    # the whole point: this list is *not* behind a summary
    assert "<details" not in card, "the error list is inside a disclosure again"
    assert card_end < html.index('<details class="events-box">'), \
        "the error card sits below the power-events disclosure it is meant to lead"
    assert 'id="events"' in html[html.index('<details class="events-box">'):], \
        "the power list left its disclosure"

    js = _code(client.get("/static/page-ups.js").text)
    feed = _event_feed_path(js)
    assert "Dash.eventsPager($('#events-errors'), errors, {" in feed, \
        "the error list is not rendered through the shared pager"
    assert "label: 'Connection & errors'" in feed, "the error list has no accessible name"
    assert "$('#ups-errors-card').hidden = errors.length === 0;" in feed, \
        "the error card no longer appears and disappears with its rows"
    # and the pager state is per `<ul>` (`app.js`: a `WeakMap` keyed by the list), so the two
    # lists page independently: this is the contract that makes a second call site free
    app_js = _code(client.get("/static/app.js").text)
    assert "const feedPagers = new WeakMap();" in app_js
    assert "feedPagers.get(list)" in app_js and "feedPagers.set(list, pager)" in app_js


def test_the_ups_error_card_adds_no_stylesheet_selector(client) -> None:
    """The second feed is markup + the existing vocabulary, and `dash.css` must stay that way.

    Pinned as the *absence* of a rule, because the temptation this writes back into is a
    `#ups-errors-card` block restating the feed's scroll or the pager's strip: `ul.events {` and
    `.events-pager {` are each declared exactly once in the sheet (the disclosure pin already
    holds that), and the error card carries its own gap as an inline `margin-top` like every
    other section on this page rather than through an id rule.
    """
    css = _css(client)
    for selector in ("#ups-errors-card", "#events-errors"):
        assert selector not in css, f"dash.css grew a rule for {selector}"
    assert css.count("ul.events {") == 1 and css.count(".events-pager {") == 1

    html = client.get("/ups").text
    assert 'id="ups-errors-card" style="margin-top:.85rem"' in html, \
        "the error card no longer carries the page's own section gap inline"


def test_the_ups_events_disclosure_is_a_quiet_disclosure_not_a_new_component(client) -> None:
    """The `/ups` summary borrows the card header's rhythm and no new palette (task 03).

    Pinned on the served stylesheet because a CSS edit is invisible until someone looks: the
    `\\25B8`/`\\25BE` caret pair says open/closed in a **shape** as well as a colour, the webkit
    marker is hidden so the browser's own triangle does not double it, and this `<summary>`
    carries the card header's ground and bottom rule because it *replaces* that header instead of
    sitting inside the body like `charts-box`'s toggle does. The `> .body` padding restatement is
    the quiet one: `.card > .body` is a **child** selector, so a body moved inside a disclosure
    silently loses its padding and the feed renders flush to the card edge.

    What the block must not do is grow a verdict colour (open/closed is not a grading) or
    re-state the shared feed rules — `ul.events`' bounded scroll and `.events-pager`'s strip are
    class-based and resolve inside the disclosure unchanged, so a second copy here would be a
    second thing to keep in sync. The undeclared-token audit itself stays the existing
    `test_no_stylesheet_rule_uses_an_undeclared_token`'s job, untouched.
    """
    css = _css(client)
    start = css.index("details.events-box { ")
    block = css[start:css.index(".host-charts {", start)]

    assert 'details.events-box > summary::before { content: "\\25B8"' in block, \
        "the toggle has no caret shape"
    assert 'details.events-box[open] > summary::before { content: "\\25BE"; }' in block, \
        "open and closed differ only in colour"
    assert "details.events-box > summary::-webkit-details-marker { display: none; }" in block, \
        "the browser's own marker doubles the caret"
    assert "cursor: pointer" in block and "list-style: none" in block, \
        "the summary no longer reads as a control"
    # it replaces the card header, so it carries the header's ground and bottom rule
    assert "border-bottom: 1px solid var(--border)" in block, \
        "a closed card no longer reads as its heading"
    assert "color-mix(in srgb, var(--bg-raised) 70%, var(--bg-sunken))" in block, \
        "the summary lost the header's sunken ground"
    # open: the label steps back, and no margin — the `.body` below carries the spacing
    assert "details.events-box[open] > summary { color: var(--text-faint); }" in block, \
        "an open summary does not de-emphasise"
    assert "margin-bottom" not in block, "the open summary stacks a gap on top of the body's"
    # the child-selector gotcha that task 01's markup introduced
    assert "details.events-box > .body { padding: .8rem; }" in block, \
        "the feed body lost its padding inside the disclosure"

    for token in ("var(--ok)", "var(--warn)", "var(--fail)", "var(--accent)"):
        assert token not in block, f"the disclosure graded open/closed with {token}"
    assert ".sev-" not in block, "the disclosure invented a verdict family"

    # one copy of each shared feed rule, class-based, resolving inside the disclosure as elsewhere
    assert css.count("ul.events {") == 1, "ul.events is styled twice — the bounded scroll drifted"
    assert css.count(".events-pager {") == 1, "the pager strip is styled twice"
    # the class this block styles is the class the page renders
    assert 'class="events-box"' in client.get("/ups").text, \
        "the stylesheet styles a disclosure no page renders"

    # Phase 26's guard, here because it is the disclosure's own claim: the *second* feed this
    # page renders borrowed `section.card` + `ul.events` + `.events-pager` and nothing else, so
    # this block may not have grown a rule for it either. A second style for a second list is a
    # second copy of the bounded scroll and the pager strip to keep in sync — the phase-19
    # anti-pattern, one task later. (`test_the_ups_error_card_adds_no_stylesheet_selector` holds
    # the same guard for the card's own section, plus the inline-gap pin.)
    for selector in ("#ups-errors-card", "#events-errors"):
        assert selector not in block and selector not in css, \
            f"dash.css styles the second feed through {selector} instead of the shared classes"


def test_the_pager_returns_to_page_1_when_the_events_change(client) -> None:
    """New events reset the window; the same events do not.

    Resetting on every poll would snap `next` back within one interval, so page 2 could never
    be read; never resetting lands an operator on page 3 of a list that changed underneath
    them. The page key is the set of events, not the clock.
    """
    app_js = _code(client.get("/static/app.js").text)
    body = app_js[app_js.index("function eventsPager("):]
    assert "signature !== pager.signature" in body, "the pager no longer notices new events"
    reset = body[body.index("signature !== pager.signature"):]
    assert reset.index("pager.page = 0") < reset.index("paintEventFeed"), \
        "new events do not reset the page before the feed is drawn"
    assert "if (pager.markup !== markup)" in app_js, \
        "every poll rewrites 50 rows and throws away the reader's scroll position"


def test_system_event_feed_queries_the_source_transitions_are_stored_under(client) -> None:
    """Host transitions are stored under the *dashboard* name, not the sample source.

    `poller.py` logs `Event(ts, self.dashboard, …)` — host jobs write `system`, the way
    the UPS job writes `ups` — while *samples* use `host`. The `/system` feed queried
    `source=host` since the first commit and therefore always rendered "no transitions
    yet", even with a real outage (a gateway disconnect) sitting in the store. Pinned on
    the served bytes because there is no JS test runner (a locked anchor).
    """
    js = client.get("/static/page-system.js").text
    feed = _event_feed_path(js)
    url = re.search(r"fetchJSON\([`'](/api/events[^`']*)[`']\)", feed)
    assert url, "the /system page no longer fetches the event feed"
    assert "source=system" in url.group(1), \
        "the /system event feed must ask for the source the poller stores events under"
    assert "source=host" not in url.group(1), \
        "source=host matches no stored event — the feed is empty forever"


def test_system_footnote_prints_the_window_it_actually_measured(client) -> None:
    """`Δ<window>` is the page's promise that a rate is a measurement (invariant 2), so the
    number behind it has to come from the measurement.

    The `window_seconds` beside the fleet is `HOST_INTERVAL_SECONDS`, while the window behind a
    rate is the estimator's `RATE_WINDOW_SECONDS` — equal at the defaults, which is why the
    footnote could quote the poll interval and look right. Set `RATE_WINDOW_SECONDS=30` and it
    would have labelled every rate on the page with a window it never used. The footnote now
    reads each host's own measured `window_seconds`, and prints a range when they disagree.
    """
    js = client.get("/static/page-system.js").text
    assert "function windowLabel(" in js, "the footnote lost its measured-window helper"
    footnote = js[js.index("$('#foot-note').textContent"):js.index("await Promise.all(chartJobs)")]
    assert "windowLabel(" in footnote
    assert "host.window_seconds" in footnote, \
        "the footnote is quoting the poll interval as a measurement again"
    # a footnote that says "window" and a page that says "poll" must stay two separate claims
    assert "poll ${Math.round(state.pollMs / 1000)}s" in footnote


def test_no_per_core_visual_library_survives_the_page(client) -> None:
    """The per-core heat bars left `/system` and `charts.js` with them (PLAN.md *Dropped
    visuals* is about what the pages draw, not what the store keeps).

    `renderCores` had one caller — the hero-card per-core block deleted in task 02 — so
    keeping it would be dead markup generating unstyled `.core` spans; `.cores` was the CSS
    that block needed. Both are checked absent here so neither can come back as a
    half-change, while `sparkline`/`LineChart` stay for phase 04 and the UPS page.
    """
    assert "renderCores" not in client.get("/static/charts.js").text
    css = client.get("/static/dash.css").text
    assert ".cores" not in css
    for asset in ASSETS:
        assert "core_usage" not in _code(client.get(asset).text), f"{asset} plots per-core"
    # what phase 04 and the other pages still chart from
    for name in ("LineChart", "sparkline", "renderLegend"):
        assert name in client.get("/static/charts.js").text


def test_sparkline_ships_the_fixed_scale_and_verdict_options(client) -> None:
    """Phase 04 turns `/llm` cells into sparkline rows, so the shared `sparkline()` must
    behave like `llm_monitor`'s `drawSpark` (the task-02 contract, NOTES-chart-set).

    Pinned on the served bytes because there is no JS test runner (a locked anchor). What
    matters is not the option names but the semantics behind each one: a percent metric
    that silently rescaled to its own data would make an 8 % KV cache and a 92 % spike the
    same squiggle, and a stroke coloured from a page-invented threshold would break the
    one-colour-language rule the same way.
    """
    charts_js = client.get("/static/charts.js").text
    body = charts_js[charts_js.index("function sparkline("):charts_js.index("window.DashCharts")]

    # the phase grep criterion, as a test: the options are really in the shipped file
    hits = [ln for ln in charts_js.splitlines()
            if re.search(r"fixedMax|align|severity", ln)]
    assert len(hits) >= 3, "the sparkline upgrade is not in the served charts.js"
    for opt in ("fixedMax", "align", "labels", "severity", "minPoints", "span", "format",
                "minSpan"):
        assert opt in body, f"sparkline() lost its `{opt}` option"

    # fixedMax: the data clamps to the axis, never the axis to the data
    assert "Math.min(Math.max(v, lo), hi)" in body, \
        "a fixedMax sparkline rescales to its own data again"
    # align:'right' grows within a real time window (span seconds), not a sample count
    assert "x1 - o.span" in body, "align:'right' forgot the window it grows inside"
    # verdict colour comes from the theme tokens only; unrated is faint grey, never green
    for token in ("cssVar('--ok')", "cssVar('--warn')", "cssVar('--fail')",
                  "cssVar('--text-faint')"):
        assert token in body, f"sparkline() stopped taking its colour from {token}"
    assert ".sev-" not in body, "sparkline invented a parallel severity vocabulary"
    # the `now / max` foot llm_monitor prints, via the caller's format callback
    assert "now ${fmt(last.value)}" in body and "max ${fmt(dataMax)}" in body
    # never a confident line through one point, and the foot quotes data, not the padded axis
    assert "minPoints: 2" in body and "no history" in body
    # ASSUMPTION (task 02): no animation at all, so prefers-reduced-motion holds by design
    assert "transition:" not in body and "animation:" not in body


# ---- the battery glyph (phase 05 task 02) ---------------------------------
#
# `DashCharts.battery()` is the one visual in this app whose *shape* is the data: the fill
# is the charge. That makes the honesty rules heavier here than anywhere else — a fill
# rounded up to look reassuring, a colour invented for an unrated cell, or a state only
# readable as green-vs-red would each turn a glance at the battery into a wrong claim.
# There is no JS test runner (a locked anchor), so the construction is pinned on the served
# bytes and shown in a browser (`data/logs/ups-glyph-*.png`).

def _battery_js(client: TestClient) -> str:
    """The glyph's code as served (state table + body), comments stripped.

    Prose cannot satisfy these assertions, and the phrase table the accessible name is
    built from is part of the component, so the slice starts above `function battery`.
    """
    charts = client.get("/static/charts.js").text
    body = charts[charts.index("const BATTERY_STATES"):charts.index("window.DashCharts")]
    assert "function battery(container, opts)" in body
    return _code(body)


def test_battery_glyph_is_exported_from_the_shared_chart_library(client) -> None:
    """The phase's own grep criterion, as a test: exactly one glyph, and it is public."""
    charts = client.get("/static/charts.js").text
    assert charts.count("function battery") == 1
    exports = charts[charts.index("window.DashCharts"):]
    assert re.search(r"\bbattery\b", exports), "DashCharts.battery is not exported"
    # the wrapper the stylesheet sizes, added by the component rather than each caller
    assert ".battery {" in _css(client) and ".battery svg" in _css(client)


def test_battery_fill_is_the_charge_and_is_never_padded(client) -> None:
    """2 % must look nearly empty, and 0 % must leave an empty shell, not a stray pixel."""
    body = _battery_js(client)
    # clamped to the scale, and the clamp is the only thing that touches the number: a
    # minimum visible width would be a reassuring battery over a flat one
    assert "Math.max(0, Math.min(100," in body
    assert "(pctValue / 100) * inner.w" in body, "the fill stopped being a fraction of charge"
    assert not re.search(r"Math\.max\(\s*[0-9.]*[1-9]\s*,", body), \
        "the charge fill got a minimum width — a small charge would look bigger than it is"
    # nothing is drawn for a cell at zero, and the plate it fills is a clip, so a low fill
    # cannot leak outside the rounded interior
    assert "pctValue > 0" in body
    assert "<clipPath" in body and 'clip-path="url(#' in body
    # an empty cell is the sunken plate, never a transparent hole in the card
    assert "cssVar('--bg-sunken')" in body


def test_battery_colours_come_from_the_verdict_tokens_only(client) -> None:
    """The verdict paints; an unrated cell draws a grey shape and no colour at all."""
    body = _battery_js(client)
    for token in ("cssVar('--ok')", "cssVar('--warn')", "cssVar('--fail')"):
        assert token in body, f"the glyph stopped taking its colour from {token}"
    # no verdict → muted outline, and a measured charge in faint grey at half strength: a
    # shape, not a judgement (an unknown number must never look green)
    assert "cssVar('--text-muted')" in body and "cssVar('--text-faint')" in body
    assert ' opacity=".5"' in body, "an unrated charge is drawn with the same weight as a rated one"
    assert ".sev-" not in body, "the glyph invented a parallel severity vocabulary"
    assert "severityFor(" not in body, "the glyph compares the charge to a threshold itself"


def test_battery_states_are_readable_without_colour(client) -> None:
    """Every state has a *shape*, so the glyph survives monochrome and colour-blindness.

    on battery = dashed outline, charging = bolt, unknown = a dash pattern through the
    body, online = a plain solid shell. A word the page did not intend falls back to
    `unknown` rather than to a confident "on line".
    """
    body = _battery_js(client)
    assert 'BATTERY_STATES.indexOf(o.state) >= 0' in body, \
        "an unrecognised state would be drawn as some other state"
    assert 'state === \'onbattery\'' in body and 'stroke-dasharray="7 5"' in body, \
        "the on-battery outline is no longer dashed"
    assert "state === 'charging'" in body and 'd="M13 2 L3 14' in body, "the charging bolt is gone"
    assert "state === 'unknown'" in body and 'stroke-dasharray="5 6"' in body, \
        "an unknown charge no longer draws a dash through the body"
    # and the unknown case really is *no fill*: the shape has to say it on its own
    assert "pctValue != null" in body


def test_battery_glyph_names_itself_and_can_say_it_once(client) -> None:
    """`role="img"` + `<title>` built from the inputs, with an explicit `aria-hidden` opt-out."""
    body = _battery_js(client)
    assert 'role="img"' in body and "<title>" in body and "aria-label=" in body
    for phrase in ("Charge ", " percent", "Charge unknown", "on line", "on battery",
                   "charging", "state unknown"):
        assert phrase in body, f"the accessible name lost {phrase!r}"
    # the label is a UPS name from upsd, so it goes through the one escaper
    assert body.count("escapeHtml(name)") == 2, "<title> or aria-label stopped escaping the label"
    assert 'aria-hidden="true"' in body, "the decorative opt-out for a duplicate hero number is gone"


def test_battery_glyph_scales_with_its_container_and_never_animates(client) -> None:
    """One `viewBox` + `preserveAspectRatio` for a phone and a 27" monitor; no motion at all."""
    body = _battery_js(client)
    assert 'viewBox="0 0 ${W} ${H}"' in body
    assert 'preserveAspectRatio="xMidYMid meet"' in body, "the glyph stopped scaling with its box"
    assert "ResizeObserver" not in body, "the glyph redraws on resize instead of scaling"
    assert "transition" not in body and "animation" not in body
    css = _code(_css(client))
    wrapper = re.search(r"\.battery \{([^}]*)\}", css)
    inner = re.search(r"\.battery svg \{([^}]*)\}", css)
    assert wrapper and inner, "dash.css no longer sizes the glyph box"
    assert "width: 100%" in wrapper.group(1) and "max-width" in wrapper.group(1), \
        "the glyph is not capped inside its container"
    assert "width: 100%" in inner.group(1) and "height: auto" in inner.group(1), \
        "the svg would stretch instead of keeping the viewBox ratio"
    both = wrapper.group(1) + inner.group(1)
    assert "transition" not in both and "animation" not in both


# ---- the `/ups` hero row (phase 05 task 03) ------------------------------
#
# The card used to be nine equal `.metric` cells in which charge, load and runtime were the
# same size as the battery amperage. These pin the shape that replaced it on the served
# bytes (a locked anchor: no JS test runner), because the whole point of the row is a size
# and colour hierarchy a later "tidy up" can quietly flatten back to nine equal cells.

def _ups_card_js(client: TestClient) -> str:
    """The card markup as served, from `upsCard()` to `renderCard()`."""
    js = client.get("/static/page-ups.js").text
    return js[js.index("function upsCard("):js.index("function renderCard(")]


def test_ups_card_opens_with_the_glyph_and_three_heroes(client) -> None:
    """Charge / Load / Runtime are the card's three largest elements, next to the glyph.

    `data-sev` names the verdict path each slot colours itself from, the same convention the
    `/system` host card uses — so "which number is coloured by what" is readable in the
    markup, and a rename that disconnects the page from `/api/ups/snapshot` fails here
    instead of shipping a card of `n/a`.
    """
    card = _ups_card_js(client)
    assert '<div class="ups-hero">' in card, "the hero row left the top of the card"
    assert 'data-k="glyph"' in card, "the battery glyph is not part of the hero row"
    slots = re.findall(r'<div class="hero[^"]*" data-k="([^"]+)"', card)
    assert slots == ["charge", "load", "runtime"], \
        "the hero row is no longer charge / load / runtime in the agreed order"
    for hook in ("severity.charge_pct", "severity.load_pct", "severity.battery_runtime"):
        assert hook in card, f"the card no longer names {hook} as a colour source"
    # the hero row is the first thing in the card body, above the health checks and commands
    assert card.index("ups-hero") < card.index('data-k="checks"')
    assert card.index("ups-hero") < card.index('data-k="commands"')


def test_ups_heroes_take_their_colour_from_the_payload(client) -> None:
    """Three `Dash.hero()` calls, three payload verdicts, no JS threshold.

    The charge hero carries **no** `.bar`: the glyph beside it is that same value drawn as a
    shape, and one value drawn twice in one row is the pattern this app avoids (load, which
    has no other shape, keeps its bar). Runtime prose comes from `runtimeText()` alone, and
    a runtime nobody estimated is passed as `null` so `hero()` renders the faint, uncoloured
    unknown rather than the string `n/a` styled like a measurement.
    """
    js = client.get("/static/page-ups.js").text
    body = js[js.index("function renderCard("):js.index("// ---- command dialog")]
    assert body.count("Dash.hero(q(") == 3, "the hero row is not three hero numbers"
    for verdict in ("verdicts.charge_pct", "verdicts.load_pct", "verdicts.battery_runtime"):
        assert verdict in body, f"{verdict} never reaches a hero"
    charge = body[body.index("Dash.hero(q('charge')"):body.index("Dash.hero(q('load')")]
    assert "bar" not in charge, "charge grew a second shape when the glyph already is one"
    load = body[body.index("Dash.hero(q('load')"):body.index("Dash.hero(q('runtime')")]
    assert "bar: true" in load, "load lost its bar"
    assert "runtimeText(n.battery_runtime)" in body, "runtime prose bypasses runtimeText()"
    runtime = body[body.index("Dash.hero(q('runtime')"):]
    assert "n.battery_runtime == null ? null" in runtime, \
        "an unmeasured runtime is rendered as a measurement"
    assert "severityFor(" not in body


def test_ups_secondary_electrical_row_is_demoted_not_deleted(client) -> None:
    """Line in, output, battery volts and amps, battery °C: still there, visibly second.

    These are the numbers you reach for *while* the UPS is on battery, so they were demoted
    rather than folded into the disclosure — and they stay one step down (smaller, muted) so
    the three verdicts remain the largest elements, which is also what keeps the card from
    growing so tall that two stop fitting side by side on a laptop.
    """
    card = _ups_card_js(client)
    assert 'class="metrics ups-electrical"' in card
    for key in ("line", "out", "batt", "amps", "temp"):
        assert f'data-k="{key}"' in card, f"the electrical row lost {key}"
    assert card.index("ups-electrical") > card.index("ups-hero")
    css = _code(_css(client))
    rule = re.search(r"\.ups-electrical \.metric \.value\.sm \{([^}]*)\}", css)
    assert rule, "dash.css no longer styles the secondary row"
    assert "var(--text-muted)" in rule.group(1), "the secondary row is not muted"
    sizes = re.findall(r"font-size: ([\d.]+)rem", rule.group(1))
    assert sizes and float(sizes[0]) < 1.3, "the secondary row competes with the heroes"
    # `n/a` is fainter than a muted reading — neither real driver reports a battery temperature
    null_rule = re.search(r"\.ups-electrical \.metric \.value\.sm\.is-null \{([^}]*)\}", css)
    assert null_rule and "var(--text-faint)" in null_rule.group(1), \
        "an unmeasured secondary value is not faint, so it reads like a number"


def test_ups_glyph_state_comes_from_the_api_fields(client) -> None:
    """`glyphState()` maps `on_battery` + `charger_status` — and `full` is **not** charging.

    The mapping is presentation, so it lives in the page (task 02's assumption), but it is
    still a mapping the real drivers exercise: neither UPS here exports
    `battery.charger.status`, so the fallback that reads a state the API rated `ok` is what
    draws a solid shell on both of them. Nothing here re-reads `ups.status` —
    `test_the_page_does_not_re_parse_nut_status_flags` holds that line.
    """
    js = _code(client.get("/static/page-ups.js").text)
    glyph = js[js.index("function glyphState("):js.index("function drawGlyph(")]
    assert "item.on_battery" in glyph and "'onbattery'" in glyph
    assert "charger === 'chg'" in glyph and "'charging'" in glyph
    assert "charger === 'dchg'" in glyph, "a discharging charger token is on battery too"
    assert "charger === 'full'" in glyph and "'online'" in glyph, \
        "a full, online battery must not be drawn as charging"
    assert "item.states" in glyph, "a driver with no rich status lost its state entirely"
    assert "'unknown'" in glyph, "an unknown state now degrades to a confident 'on line'"


def test_ups_glyph_repaints_only_when_something_visible_changes(client) -> None:
    """Charge jitters by a tenth of a percent every poll; the `<svg>` does not rebuild on it.

    Rebuilding would re-resolve the theme tokens and re-announce the accessible name every
    `NUT_INTERVAL_SECONDS` for a difference no eye can see. `decorative: true` is the
    component's documented opt-out — the charge hero and the state chips already say
    "Charge 100 percent, on line", and a screen reader should not hear it twice.
    """
    js = _code(client.get("/static/page-ups.js").text)
    draw = js[js.index("function drawGlyph("):js.index("function upsCard(")]
    assert "DashCharts.battery(" in draw
    assert "cell.dataset.drawn === drawn" in draw, "the glyph rebuilds on every poll"
    assert "decorative: true" in draw, "the glyph duplicates the hero number in a11y"
    assert "glyphState(item)" in draw


def test_ups_hero_row_makes_room_for_the_glyph(client) -> None:
    """The glyph gets a real column, and the row stacks rather than clipping on a phone.

    The track floor is the widest runtime prose the page prints (`9h 59m`) — a number that
    cannot wrap needs the floor to be its own width, or the row grows a clipped `1h 28`.
    """
    css = _code(_css(client))
    row = re.search(r"\.ups-hero \{([^}]*)\}", css)
    assert row, "dash.css lost the UPS hero row"
    assert "minmax(112px, 156px) minmax(0, 1fr)" in row.group(1), "the glyph has no column"
    assert "align-items: center" in row.group(1)
    heroes = re.search(r"\.ups-hero \.heroes \{([^}]*)\}", css)
    assert heroes and "minmax(min(140px, 100%), 1fr)" in heroes.group(1), \
        "a hero track can now clip the widest runtime prose"
    at = css.index("@media (max-width: 620px)")
    block = css[at:at + 240]
    assert ".ups-hero" in block and "minmax(0, 1fr)" in block, "the row never stacks"


def test_every_ups_chart_names_itself_for_assistive_tech(client) -> None:
    """The four trend plots on `/ups` carry an accessible name, like every other chart here.

    `AGENTS.md` states the convention as *every* chart names itself: `LineChart` puts
    `role="img"` + `aria-label` on the `<svg>` when the caller passes `ariaLabel`, because
    the legend is a sibling that labels nothing and an unlabelled plot is silence. `/system`
    (phase 03) and `/llm` (phase 04) were pinned; these four were the stragglers, so the
    rule is now pinned on every page that draws one.
    """
    js = client.get("/static/page-ups.js").text
    charts = js[js.index("function makeCharts("):js.index("function points(")]
    assert charts.count("ariaLabel:") == 4, "a `/ups` chart lost its accessible name"
    for phrase in ("Battery charge", "Battery runtime", "Battery and line voltage", "UPS load"):
        assert phrase in charts, f"the {phrase!r} chart names nothing readable"


# ---- the `/llm` layout (phase 04 task 03) ---------------------------------
#
# The drift this phase fixes was a 14-cell grid where everything was the same size and
# nothing showed recent shape. These tests pin the *shape* the page committed to on the
# served bytes (a locked anchor: no JS test runner), so a regression to "all cells equal"
# fails a test rather than a screenshot.

def test_llm_page_colours_from_the_payload_not_from_js_thresholds(client) -> None:
    """`page-llm.js` paints the KV verdict `severity.py` produced; it owns no threshold.

    Both `severityFor(value, 75, 90)` call sites are gone (the task's explicit work item):
    the KV row takes `severity` from the rated ratio cell, the fleet KV bar was deleted
    with the summed card, and every unrated number — throughput above all, because 0 tok/s
    on an idle server is healthy — draws no colour at all.
    """
    js = client.get("/static/page-llm.js").text
    assert "severityFor(" not in js, "the LLM page re-invented a threshold"
    assert "severityFrom" in js
    # the KV verdict comes from the payload cells `sources/llm.py` rates
    kv = js[js.index("case 'cache':"):js.index("case 'ttft':")]
    assert "kv_cache_usage_ratio" in kv and "gpu_cache_usage" in kv and "severity" in kv


def test_llm_engine_panel_leads_with_two_throughput_heroes(client) -> None:
    """Decode and prompt are the largest elements per engine; the rest is visibly secondary.

    The hero row is `Dash.hero()` markup (2.4rem via `.hero`), built from the `hero: true`
    flags in `CELLS`, and throughput carries **no** severity — `severity.py` has no
    throughput row and the page invents none (the neutral-ink decision in NOTES-chart-set,
    mirroring the `/system` NET precedent). The provenance tag stays in the hero's `.sub`
    with the exact `source` as the tooltip: removing it to look cleaner is a regression.
    """
    js = client.get("/static/page-llm.js").text
    panel = js[js.index("function enginePanel("):js.index("function renderPanel(")]
    assert 'data-hero="${cell.key}"' in panel, "the hero row is not flag-driven markup"
    assert '<div class="heroes">' in panel, "the hero row left the engine panel"
    heroes = re.findall(r"{ key: '(\w+)'[^}]*?hero: true", js)
    assert heroes == ["decode", "prompt"], "the hero row is no longer the two throughputs"
    # driven by flags, not fourteen identical cells. Phase 07 task 03 lifted the summary rows
    # out of the panel into the stats strip above it, so what is left here is the pair plus
    # the latency rows the strip does not print — never a fourteen-cell grid again.
    assert "SPARK_CELLS" in js and "ALARM_CELLS" in js
    assert js.count("spark: '") >= 2, "the panel lost the latency sparkline rows it kept"
    assert js.count("hero: true") == 2, "the hero row is no longer exactly two numbers"
    # the hero call must not pass a severity — unrated by design
    hero_call = js[js.index("const node = hero("):js.index("if (node) node.title")]
    assert "severity" not in hero_call, "throughput invented a verdict"
    # provenance intact: the tag is generated from the cell's `source`, never hardcoded
    assert "provenance" in js and "Δ" in js
    assert "node.title = value.source" in js


def test_llm_provenance_tag_prints_the_window_the_payload_sent(client: TestClient) -> None:
    """`Δ2.0s` on `/llm` is the cell's own `window`, never a config echo (phase 23).

    The window moved from 10 s to one poll interval without touching the page: `provenance()`
    reads `cell.window`, which is the number `tests/test_llm_source.py` pins to the LLM span, and
    both spell the label with the same one-decimal rounding (`delta_label` in
    `tests/rate_window_contract.py` is that rounding, used by both payload pins). A page printing
    the configured interval instead would advertise a window no poll measured (rule 2), and a
    literal `Δ10.0s` in the script is the same lie with the number typed in.
    """
    js = client.get("/static/page-llm.js").text
    prov = js[js.index("function provenance("):js.index("function humanNumber(")]
    assert "`Δ${cell.window.toFixed(1)}s`" in prov, \
        f"the Δ tag is no longer built from the window the cell carries: {prov}"
    assert delta_label(LLM_WINDOW) == "Δ2.0s", "the rounding the page and the pins share moved"
    assert "rate_window_seconds" not in js, "the page echoes a config window beside a measurement"
    assert "Δ10.0s" not in js, "a hard-coded Δ is an invented window (rule 2)"


def test_every_llm_cell_carries_a_window_sparkline_with_percentile_feet(client) -> None:
    """Each panel row draws its own sparkline over the *selected* window and prints mean
    **and** p95 without a hover.

    The window is honest time (`align: 'right'` + `span`) and the p95 comes from the
    snapshot's histogram cells — p95 needs no stored series. The `only` scopes are what keep
    a gufo panel from showing a latency mystery and a vLLM strip card from showing a
    spec-decode row it cannot fill.

    Phase 07 task 03 moved the percent and count rows to the stats strip, so the plotted
    percent series left the cell list and the axis guarantee moved with it: the KV trend
    chart pins `yMax: 100` (an 8 % window that once held a 92 % spike must not read flat),
    and the strip converts its 0-1 ratios to per cent in `cellValue()` — a bar cannot
    autoscale, so it cannot lie that way either. The `fixedMax`/`minSpan` options stay
    plumbed through `drawSparks()` and are pinned on the component itself by
    `test_sparkline_ships_the_fixed_scale_and_verdict_options`: a count sparkline that comes
    back must not get an axis finer than one request.
    """
    js = client.get("/static/page-llm.js").text
    sparks = js[js.index("function drawSparks("):js.index("function renderFleet(")]
    assert "DashCharts.sparkline(" in sparks
    for opt in ("align: 'right'", "span: state.range", "fixedMax", "labels: { max: true }"):
        assert opt in sparks, f"cell sparklines lost `{opt}`"
    # the one percent series still plotted owns a fixed 0-100 axis; seconds stay ms
    charts = js[js.index("function makeCharts("):js.index("function pointsFor(")]
    assert "yMax: 100" in charts, "the KV trend chart no longer pins its 0-100 axis"
    assert "scale: 1000" in js and "cell.scale || 1" in sparks
    # every spark cell declares its history series in the markup it is built from
    assert 'data-spark data-metric="${cell.spark}"' in js
    # percentile foot lines: mean big in the row, p95 beneath, n/a when nothing measured
    assert "function p95Value(" in js
    for name in ("time_to_first_token_seconds__p95", "time_per_output_token_seconds__p95",
                 "request_queue_time_seconds__p95"):
        assert name in js, f"{name} no longer feeds a foot line"
    assert "p95 n/a" in js
    assert 'data-foot' in js
    # engine-scoped rows: gufo never grows a TTFT row, vLLM never a spec-accept row
    assert "only: ['vllm']" in js and "only: ['gufo']" in js
    scoped = js[js.index("function sparkCellsFor("):js.index("function enginePanel(")]
    assert "cell.only" in scoped
    assert "minSpan: cell.minSpan" in sparks, "cell minSpan never reaches the sparkline"


def test_llm_sparklines_and_charts_cost_one_batched_history_request(client) -> None:
    """One `/api/llm/history` call per refresh feeds charts *and* every sparkline row.

    The endpoint answers a metric list for every engine, and unknown names come back as
    empty series on purpose — so the page asks for the full cell set once instead of one
    XHR per cell, and the two series phase 04 added (`tpot_seconds`, `spec_accept_rate`)
    must be in that list or those rows are permanent "no history" slots.
    """
    js = client.get("/static/page-llm.js").text
    # comments aside, exactly one fetch hits the endpoint: one request, every metric
    calls = re.findall(r"fetchJSON\(\s*`/api/llm/history", _code(js))
    assert len(calls) == 1, "the page makes more than one history request again"
    assert "HISTORY_SERIES.join" in js and "SPARK_CELLS.map((cell) => cell.spark)" in js
    request = js[js.index("async function refreshHistory("):js.index("function drawSparks(")]
    assert "metrics=${HISTORY_SERIES.join" in request
    assert "range=${state.range}" in request
    # and the endpoint really answers every name the page asks for
    for name in ("tpot_seconds", "spec_accept_rate", "ttft_seconds", "queue_seconds",
                 "kv_cache_usage", "requests_running", "requests_waiting",
                 "prefix_cache_hit_ratio"):
        assert name in HISTORY_METRICS, f"llm.{name} is not stored, so its spark is dead"


def test_llm_alarm_cells_exist_only_while_there_is_an_incident(client) -> None:
    """`preemptions` / `device_lost` are absent at zero and red chips above zero.

    The rule is the *existence of an incident*, not a graded threshold — `sources/llm.py`
    already treats any non-zero `gufo_device_lost_total` as one. The chip reuses the shared
    `.chip.fail` vocabulary; nothing new is painted, and a container emptied at zero means
    the row does not exist rather than showing a permanent ignored 0.

    Phase 07 task 03 renders them on the engine's strip card (the summary you read first)
    instead of inside the panel, so the two `alarm: true` rows live in `STRIP_ROWS` and
    `ALARM_CELLS` filters them out of it — counted with the comments stripped, because the
    docstring on that table explains the flag by name.
    """
    js = client.get("/static/page-llm.js").text
    alarms = js[js.index("function renderAlarms("):js.index("function makeCharts(")]
    assert "class=\"chip fail\"" in alarms, "the alarm chip left the shared fail vocabulary"
    assert "value.value > 0" in alarms
    assert "host.hidden = chips.length === 0" in alarms
    assert 'data-alarm="${cell.key}"' in alarms
    assert _code(js).count("alarm: true") == 2
    assert "ALARM_CELLS = STRIP_ROWS.filter" in js, "the alarm rows are not strip rows"
    # the panel no longer carries a second container for the same incident
    panel = js[js.index("function enginePanel("):js.index("function renderPanel(")]
    assert 'data-k="alarms"' not in panel, "the alarm chips are drawn twice"
    strip = js[js.index("function stripCard("):js.index("function renderStripCard(")]
    assert 'data-k="alarms"' in strip, "the alarm chips left the strip card"


# ---- the `/llm` stats strip (phase 07 task 03) ---------------------------
#
# `llm_monitor`'s shared strip (`index.html` ~L743), ported: one card per configured engine
# between the fleet block and the panels. Two things make it a summary instead of a second
# set of panels, and both are pinned below: every row is a cell `/api/llm/snapshot` really
# publishes, and no row is printed in the strip *and* in the panel under it.

#: row key -> the cells `cellValue()` resolves it from (`sessions.*` is the gufo slot count,
#: which is not a metrics cell). The served `STRIP_ROWS` table must match these keys exactly.
STRIP_ROW_PATHS: dict[str, tuple[str, ...]] = {
    "prompt": ("prompt_tokens_per_second",),
    "decode": ("decode_tokens_per_second",),
    "tokens_total": ("tokens_total",),
    "slots_busy": ("sessions.list", "sessions.active"),
    "running": ("requests_processing", "num_requests_running"),
    "waiting": ("requests_deferred", "num_requests_waiting"),
    "cache_hit": ("prefix_cache_hit_ratio", "prompt_cache_hit_ratio"),
    "spec_accept": ("spec_accept_rate",),
    "queue_mean": ("request_queue_time_seconds__mean",),
    "preemptions": ("num_preemptions_total",),
    "device_lost": ("device_lost_total",),
}

#: rows that are incidents, not stats: absent where the engine does not count them.
ALARM_ROW_KEYS = ("preemptions", "device_lost")


def _strip_rows(js: str) -> dict[str, str | None]:
    """The served `STRIP_ROWS` table: row key -> its `only` scope (`None` = every engine)."""
    body = _code(js)
    start = body.index("const STRIP_ROWS = [")
    table = body[start:body.index("\n];", start)]
    rows: dict[str, str | None] = {}
    for chunk in table.split("{ key: '")[1:]:
        scoped = re.search(r"only: \[([^\]]*)\]", chunk)
        rows[chunk.split("'")[0]] = scoped.group(1) if scoped else None
    return rows


def _strip_render_path(js: str) -> str:
    """Just `renderStripCard()` — the whole code path that paints one strip card."""
    js = _code(js)
    return js[js.index("function renderStripCard("):js.index("function pruneEngines(")]


def test_llm_stats_strip_sits_between_the_fleet_block_and_the_panels(client) -> None:
    """The strip is there, ships hidden, names itself, and appears only with engines.

    An unconfigured engine gets no card and no strip (invariant 3) — the section is empty in
    the markup and `page-llm.js` unhides it only when the payload has an engine to draw.
    """
    html = _code(client.get("/llm").text)
    assert 'id="strip"' in html, "/llm lost the per-engine stats strip"
    assert html.index('id="fleet"') < html.index('id="strip"') < html.index('id="engines"'), \
        "the strip is no longer between the fleet block and the engine panels"
    start = html.index('<section class="strip"')
    tag = html[start:html.index(">", start)]
    assert "hidden" in tag, "the strip no longer ships hidden"
    assert 'aria-label="Engine summary"' in tag, "the strip is a region that names nothing"
    js = client.get("/static/page-llm.js").text
    assert "$('#strip').hidden = payloads.length === 0" in js


def test_llm_strip_card_is_one_card_per_engine_of_shared_vocabulary(client) -> None:
    """`stripCard()` = `.card` + `.kv` + `.bar` + `.chip.fail`: a layout, not a new component.

    Dot, name and age in the head (reachability, the same distinction the panels and the
    fleet block draw), the KV bar, the rows keyed by payload field, the alarm container.
    """
    js = client.get("/static/page-llm.js").text
    card = js[js.index("function stripCard("):js.index("function renderStripCard(")]
    assert "card.className = 'card stat'" in card
    assert "card.dataset.engine = engine" in card, "the card stopped naming its engine"
    assert '<span class="dot idle"></span>' in card
    assert '<span class="faint mono updated"></span>' in card, "the card lost its timestamp"
    assert '<span class="bar" data-kv-bar><i></i></span>' in card, "the KV bar left `.bar`"
    assert '<dl class="kv">' in card, "the strip rows left the shared `.kv` vocabulary"
    assert 'data-row="${row.key}"' in card
    assert 'data-k="alarms"' in card
    # the wrapper is why the shared `.kv` grid has to move *inside* it: applied to the
    # wrappers, `max-content 1fr` lays two rows side by side and the card reads as a
    # column of orphaned labels (found in the browser, not in a test failure)
    css = client.get("/static/dash.css").text
    section = css[css.index("/* ---- engine stats strip"):css.index("/* ---- fleet totals")]
    assert ".strip .kv { margin: 0; grid-template-columns: 1fr; }" in section
    assert ".strip .kv > div {" in section
    assert "grid-template-columns: max-content minmax(0, 1fr)" in section
    refresh = js[js.index("async function refresh("):js.index("async function refreshEvents(")]
    assert "state.strips.get(payload.engine)" in refresh, "the strip rebuilds its cards per poll"
    assert "$('#strip').appendChild(strip)" in refresh
    assert "renderStripCard(strip, payload, stateRow)" in refresh
    prune = js[js.index("function pruneEngines("):js.index("function makeCharts(")]
    assert "state.strips" in prune and "state.panels" in prune, \
        "an engine that leaves the payload leaves a card behind"


def test_llm_strip_scopes_its_rows_to_the_engines_that_publish_them(client) -> None:
    """gufo gets slots and speculative decoding; vLLM gets running and queue time."""
    rows = _strip_rows(client.get("/static/page-llm.js").text)
    assert rows["slots_busy"] == "'gufo'" and rows["spec_accept"] == "'gufo'"
    assert rows["running"] == "'vllm'" and rows["queue_mean"] == "'vllm'"
    assert rows["waiting"] is None and rows["cache_hit"] is None and rows["tokens_total"] is None
    js = client.get("/static/page-llm.js").text
    scoped = js[js.index("function stripRowsFor("):js.index("function stripCard(")]
    assert "row.only" in scoped and "row.only.indexOf(engine)" in scoped


def test_llm_strip_rows_name_cells_the_engines_publish(client, metrics_text) -> None:
    """The strip renders what the payload sends — no row whose cell no engine produces.

    `STRIP_ROW_PATHS` mirrors the JS table; every metric cell is checked against the
    capture-parsed metrics of each engine that would render that row, so a rename in
    `sources/llm.py` fails here instead of printing a permanent `n/a` in the browser, and a
    row scoped to one engine cannot leak into the other's card.
    """
    rows = _strip_rows(client.get("/static/page-llm.js").text)
    assert set(rows) == set(STRIP_ROW_PATHS), \
        f"the served strip rows drifted: {set(rows) ^ set(STRIP_ROW_PATHS)}"
    parsed = {"gufo": parse_gufo_metrics(metrics_text("gufo")),
              "vllm": parse_vllm_metrics(metrics_text("vllm"))}
    for key, only in rows.items():
        paths = STRIP_ROW_PATHS[key]
        if paths[0].startswith("sessions."):
            continue                      # its own payload object; pinned on the JS below
        shown = {engine: metrics for engine, metrics in parsed.items()
                 if not only or engine in only}
        present = [engine for engine in shown if any(path in shown[engine] for path in paths)]
        if key in ALARM_ROW_KEYS:
            # an alarm the engine does not count simply is not there: the chip renders only
            # while non-zero, so absence *is* the zero state rather than a dead row
            assert present, f"no engine publishes {'/'.join(paths)} for the {key} alarm"
            continue
        assert len(present) == len(shown), (
            f"the {sorted(set(shown) - set(present))} card would print `{key}` as n/a forever "
            f"({'/'.join(paths)} is not published)")


def test_llm_strip_slot_count_counts_published_slots_and_never_invents_zero(client) -> None:
    """`slots busy` is a count of `/slots` rows; when /slots did not answer it is `n/a`.

    Counting rows the server published is a count of published facts. An empty list from a
    server that never answered is not a measurement of an idle engine, so the row falls back
    to the published `sessions.active` carrying the API's own `detail` string (rule 2).
    """
    js = _code(client.get("/static/page-llm.js").text)
    slots = js[js.index("case 'slots_busy':"):js.index("case 'cache':")]
    assert "sessions.source" in slots and "sessions.list" in slots
    assert "is_processing" in slots, "the count ignores the authoritative busy verdict"
    assert "sessions.detail" in slots, "the fallback lost the API's own provenance"


def test_llm_strip_kv_bar_is_coloured_by_the_payload_verdict_only(client) -> None:
    """The strip's KV bar is the page's one rated cell: `severity` in, class out.

    `sources/llm.py` rates `llm.kv_cache_usage_pct`, the ratio→percent conversion the panel
    cell used to make rides with it, and `Dash.severityFrom` is the only thing that decides a
    colour — no threshold in the page, and the stylesheet adds no palette (`ok` stays quiet
    ink, exactly like the `.cell` rows and the fleet table).
    """
    body = _strip_render_path(client.get("/static/page-llm.js").text)
    assert "severityFrom(kv.severity)" in body
    assert "cellValue(engine, metrics, sessions, 'cache')" in body
    assert "Math.max(0, Math.min(100, kv.value))" in body, "the fill stopped clamping"
    assert body.count("severityFrom") == 1, "a second strip row invented a verdict"
    css = client.get("/static/dash.css").text
    section = css[css.index("/* ---- engine stats strip"):css.index("/* ---- fleet totals")]
    assert ".stat-bar.warn .value { color: var(--warn); }" in section
    assert ".stat-bar.fail .value { color: var(--fail); }" in section
    assert ".stat-bar.ok" not in section, "a healthy KV reading must stay quiet ink"
    assert ".prov:empty" in section, "an empty provenance tag draws a pill of nothing"


def test_llm_strip_throughput_carries_provenance_without_colour(client) -> None:
    """`prompt tok/s` and `decode tok/s` keep the `Δ<window>` tag and stay ink.

    The tag is generated from the cell's `source` (never hardcoded), the exact source rides
    in the row's tooltip, and `severity.py` rates no throughput — so nothing here may paint
    it (0 tok/s on an idle engine is healthy).
    """
    js = client.get("/static/page-llm.js").text
    body = _strip_render_path(js)
    assert "row.rate ? provenance(value) : ''" in body
    assert "notes.join" in body and "value.source" in body
    assert "severityFor" not in js


def test_llm_strip_and_panel_print_no_value_twice(client) -> None:
    """One value, one home — the UPS hero row's rule, applied across two components.

    Task 03 lifted sessions, queue depth, KV pressure, the cache-hit and spec-accept percents,
    the lifetime token counter and the alarm chips out of the panel cell list rather than
    drawing them twice. The two throughput heroes are the exemption the task names: the panel
    keeps its hero row (so does `llm_monitor`, which carries the pair in both places), and
    everything else appears once. Queue time moved with its p95 foot, so the move lost nothing.
    """
    js = _code(client.get("/static/page-llm.js").text)
    start = js.index("const CELLS = [")
    panel_keys = set(re.findall(r"\{ key: '(\w+)'", js[start:js.index("\n];", start)]))
    assert panel_keys == {"decode", "prompt", "ttft", "tpot"}, \
        f"the panel cell list changed shape: {sorted(panel_keys)}"
    shared = set(_strip_rows(js)) & panel_keys
    assert shared == {"decode", "prompt"}, f"printed in the strip and the panel: {sorted(shared)}"
    body = _strip_render_path(js)
    assert "p95Value(metrics, row.key)" in body, "queue time lost its p95 in the move"


def test_llm_strip_prints_no_peak_context_number(client) -> None:
    """The phase's assumption, pinned: `llm_monitor`'s peak-ctx row does not come over.

    Its cell is `llamacpp:n_tokens_max`, a since-start maximum rather than a glance number,
    and the task says this strip gets no peak-context cell. The series stays stored and
    queryable from `/api/llm/history` — not plotting it is not removing it.
    """
    js = _code(client.get("/static/page-llm.js").text)
    assert "n_tokens_max" not in js, "/llm reads the peak-context gauge again"
    assert not [key for key in _strip_rows(js) if "peak" in key]


def test_llm_fleet_block_leads_the_page_with_the_engine_sums(client) -> None:
    """The page opens with llm_monitor's aggregate block: the sums no panel can say.

    Phase 04 retired these numbers to counts; the operator asked for the aggregate
    throughput back (`TODO.md:5`), and phase 07 restores it in `llm_monitor`'s shape —
    status dot, "all engines", an `N of M engines` tag, the note that the sums cover only
    the engines answering now, then running / waiting / prompt / decode / total tokens.
    The counts-only card it replaces (`#totals`, `f-live`, `f-active`) is gone, ids and all:
    an element nothing writes is the orphan this repo pins against.
    """
    html = _code(client.get("/llm").text)
    assert 'id="fleet"' in html, "/llm lost the aggregate block"
    assert html.index('id="fleet"') < html.index('id="engines"'), \
        "the fleet block is no longer above the engine panels"
    for part in ("fleet-dot", "fleet-count", "f-running", "f-waiting", "f-prompt",
                 "f-decode", "f-tokens"):
        assert f'id="{part}"' in html, f"/llm lost the fleet block's {part}"
    for words in ("all engines", "sums only engines answering now"):
        assert words in html, f"/llm lost the fleet block's `{words}` line"
    for gone in ('id="totals"', "f-live", "f-total", "f-active", "f-kv", "seam-note"):
        assert gone not in html, f"/llm still carries {gone} from the retired counts card"

    js = client.get("/static/page-llm.js").text
    body = _fleet_render_path(js)
    assert "block.hidden = total < 2" in body, "the fleet block no longer hides for one engine"
    assert "hidden" in _fleet_tag(html), \
        "the block no longer ships hidden, so a single engine would show a fleet row"


def test_llm_fleet_block_reads_only_paths_the_api_publishes(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """Every number the block prints is a `fleet` key of `/api/llm/snapshot`.

    The page sums nothing itself — `fleet_totals()` does — so the field table in
    `page-llm.js` is a list of API paths, and a rename in `sources/llm.py` must fail here
    rather than print a permanent `n/a` in the browser. Pinned with both engines configured
    (the keys exist, empty-handed because nothing answered) and with neither (404
    `configured: false` without dialling, invariant 3 — and the shipped block stays hidden).
    """
    with build_client(tmp_path, monkeypatch, gufo_url=DEAD_URL,
                      vllm_url=DEAD_URL) as test_client:
        fleet = test_client.get("/api/llm/snapshot").json()["fleet"]
        assert set(fleet) >= FLEET_BLOCK_PATHS, FLEET_BLOCK_PATHS - set(fleet)
        # the served field table is exactly the sum rows, in llm_monitor's order
        js = test_client.get("/static/page-llm.js").text
        table = _fleet_field_metrics(js)
        assert table == ["requests_active", "requests_waiting",
                         "prompt_tokens_per_second", "decode_tokens_per_second",
                         "tokens_total"], "the fleet row changed shape without the API"
        assert set(FLEET_SUM_PATHS) == set(table), "the block totals something the API does not"
        # and the tag's two numbers are API paths too, not arithmetic the page invented
        body = _fleet_render_path(js)
        assert "fleet.engines_total" in body and "fleet.engines_live" in body

    with build_client(tmp_path, monkeypatch) as bare:
        response = bare.get("/api/llm/snapshot")
        assert response.status_code == 404
        assert response.json()["configured"] is False
        html = _code(bare.get("/llm").text)
        assert 'id="fleet"' in html and "hidden" in _fleet_tag(html), \
            "an unconfigured engine must not leave a fleet row on the page"


def test_llm_fleet_totals_drop_an_engine_that_stopped_answering(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """A total presented as current is current: a dead engine contributes nothing.

    `fleet_totals()`'s docstring is the contract and the block is where it is read. The
    injected payload survives the dead-port polls (a failed poll keeps the last good one), so
    these are the numbers a browser would get with gufo answering and vLLM down — the live
    engine's sums verbatim, `engines_live` one of two, and not one zero where a number the
    dead engine never published would sit (rule 2).
    """
    with build_client(tmp_path, monkeypatch, gufo_url=DEAD_URL,
                      vllm_url=DEAD_URL) as test_client:
        hub = test_client.app.state.ctx.hub  # type: ignore[attr-defined]
        hub.jobs["llm:gufo"].state.payload = {
            "engine": "gufo",
            "metrics": {"decode_tokens_per_second": {"value": 41.0},
                        "prompt_tokens_per_second": {"value": 17.5},
                        "requests_processing": {"value": 2.0},
                        "requests_deferred": {"value": 1.0},
                        "tokens_total": {"value": 512.0}},
            "sessions": {"active": 2, "list": []}}
        fleet = test_client.get("/api/llm/snapshot").json()["fleet"]
        assert fleet["engines_total"] == 2 and fleet["engines_live"] == 1
        assert fleet["decode_tokens_per_second"] == pytest.approx(41.0)
        assert fleet["prompt_tokens_per_second"] == pytest.approx(17.5)
        assert fleet["requests_active"] == pytest.approx(2.0)
        assert fleet["requests_waiting"] == pytest.approx(1.0)
        assert fleet["tokens_total"] == pytest.approx(512.0)

        # and with neither engine answering, every sum is null, never a confident 0
        hub.jobs["llm:gufo"].state.payload = {"engine": "gufo", "metrics": {},
                                              "sessions": {"active": None, "list": []}}
        empty = test_client.get("/api/llm/snapshot").json()["fleet"]
        assert empty["engines_live"] == 0
        assert [empty[key] for key in FLEET_SUM_PATHS] == [None] * len(FLEET_SUM_PATHS)


def test_llm_fleet_block_proves_where_its_sums_come_from(client) -> None:
    """The seam tooltip, the excluded-engine tooltip, and an `n/a` with no unit.

    Two provenance rules the rest of the app holds to, on the one block that adds engines
    together: the prompt sum carries `fleet.seams` — the API's own words on why gufo's and
    vLLM's prompt counters are not the same quantity — and the tag's tooltip names the
    engines `fleet_totals()` left out, so a partial total says so in words and not only by
    being dimmed. And a sum the API did not publish prints `n/a` with its unit cleared: "n/a
    tok/s" would read as a measurement of nothing.
    """
    js = _code(client.get("/static/page-llm.js").text)
    body = _fleet_render_path(js)
    assert "fleet.seams" in body, "the prompt sum lost the API's seam note"
    assert "not answering — excluded from every sum below" in body, \
        "the tag no longer names the engines left out of the totals"
    assert "value == null ? ''" in body, "an n/a sum can still print a unit"

    assert "value == null ? ''" in body, "an n/a sum can still print a unit"


def test_llm_fleet_block_colours_no_number(client) -> None:
    """No verdict on the aggregate row — and no dimming of anything but the tag.

    `severity.py` rates no throughput and no queue depth (0 tok/s on an idle fleet is
    healthy), so the block renders ink: the render path touches no `severity`, calls no
    `Dash.hero()`, and the stylesheet section for the block reaches for no verdict token.
    The one coloured thing on it is the shared **reachability** dot — the same distinction
    the engine panels draw between their numbers and their header dot — and the partial-fleet
    signal is the shared `.stale` dim on the count tag, which is opacity, not a verdict.
    """
    js = _code(client.get("/static/page-llm.js").text)
    body = _fleet_render_path(js)
    assert "severity" not in body, "the fleet block invented a verdict"
    assert "hero(" not in body, "the fleet block drew a hero number it cannot rate"
    assert "setDot(" in body and "markStale(tag" in body, \
        "a dead engine no longer dims the tag or darkens the block's dot"

    css = client.get("/static/dash.css").text
    section = _css_section(css, "fleet totals")
    for token in ("var(--ok)", "var(--warn)", "var(--fail)"):
        assert token not in section, f"the fleet block coloured a number with {token}"
    assert ".fleet-head" in section and ".fleet-note" in section, \
        "the fleet block's head row lost its styling"


#: Elements the browser treats as empty, so they never open a nesting level.
_VOID_TAGS = {"meta", "link", "br", "img", "input", "hr", "source", "track", "wbr"}


def _depth_at(html: str, needle: str) -> int:
    """How deeply the `needle` sits inside `<main>` (1 = a direct child of it).

    The `~` in `#banners:empty ~ #fleet` only resolves between **siblings**, so the gap rule
    depends on the markup as much as on the stylesheet. Counting tags is enough here and keeps
    the check on the served bytes: no HTML parser, no dependency, and comments are already
    gone by the time `_code` hands the page over.
    """
    body = html[html.index("<main>"):html.index(needle, html.index("<main>"))]
    depth = 0
    for closing, tag, _attrs, self_closed in re.findall(
            r"<(/?)([a-zA-Z][\w-]*)([^>]*?)(/?)>", body):
        if self_closed or tag.lower() in _VOID_TAGS:
            continue
        depth += -1 if closing else 1
    return depth


def test_llm_section_stack_keeps_the_shared_vertical_rhythm(client) -> None:
    """Fleet block → engine summaries → engine panels sit the shared `.85rem` apart.

    `TODO.md:4`: the fleet section had no spacing between it and the engine summaries. Every
    boundary below it was already handled inline — the section under `#strip` carries
    `margin-top:.85rem` — so `#fleet` and `#strip` skipped the rhythm and the top of the page
    read as one unbroken wall. Measured in Chromium at the 16px root (`data/logs/`
    `llm-fleet-spacing*.png`), before → after:

    | gap | before | after |
    |-----|--------|-------|
    | `#fleet` → `#strip` | **0 (flush)** | 13.59px |
    | `#strip` → engine panels | 13.59px | 13.59px |
    | banner slot → `#fleet`, no banner | 13.59px | 13.59px |
    | banner slot → `#fleet`, one banner up | 13.59px | 13.59px (`margin-top: 0px`) |

    One rendered distance moves, and it is the one the operator named. What the *shape* of the
    two rules buys is that no other state can put it back:

    * `#strip`'s gap is **unconditional**, because below two engines `#fleet` is `[hidden]`
      (`display:none !important`, so it contributes nothing) and the strip is then the first
      visible section: the 13.59px below the banner slot in that state is now the strip's own
      margin rather than one borrowed from a slot above it, which is what `#fleet ~ #strip`
      would have been;
    * `#fleet`'s gap is guarded by `#banners:empty`, so the block owns its top gap exactly when
      nothing occupies the slot above it, and a banner's own `margin-bottom:.85rem` stays the
      single gap under it. An unguarded `#fleet { margin-top }` is a second rule for one gap:
      margin collapsing hides it at `.85rem`/`.85rem` today, and it doubles the moment either
      margin is changed. The empty slot keeps its inline bottom margin, so head → fleet stays
      the 1rem + .85rem the other two banner pages (`/`, `/ups`) already render.

    Pinned on the served bytes because a stylesheet "cleanup" that drops either rule is
    invisible in a diff and only shows up as a page that reads worse.
    """
    raw = _css(client)
    section = _css_section(raw, "fleet totals")
    assert "#strip { margin-top: .85rem; }" in section, \
        "the fleet block and the engine summaries render flush again (TODO.md:4)"
    assert "#banners:empty ~ #fleet { margin-top: .85rem; }" in section, (
        "the gap above the fleet block stopped belonging to the block: a banner-less page "
        "would then have it only as long as the empty banner slot keeps its inline margin")

    # one rule per element: a second one (or an unguarded `#fleet`) is the double gap
    css = _code(raw)
    for element, expected in (("#strip", {"#strip"}),
                              ("#fleet", {"#banners:empty ~ #fleet"})):
        selectors = {s.strip() for s in re.findall(rf"([^{{}}]*{element}[^{{}}]*)\{{", css)}
        assert selectors == expected, (
            f"dash.css styles {element} with {sorted(selectors)} — exactly one rule, the "
            "guarded one, or the page grows a double gap or loses the single one")

    html = _code(client.get("/llm").text)
    for element in ("banners", "fleet", "strip"):
        assert _depth_at(html, f'id="{element}"') == 1, (
            f"`#{element}` is no longer a direct child of <main>, so the `~` gap rule cannot "
            "match: rewrite the selectors for the new structure instead of dropping the gap")
    assert html.index('id="banners"') < html.index('id="fleet"') < html.index('id="strip"') \
        < html.index('id="engines"'), "the section stack was re-ordered"

    # the inline half of the rhythm, which the two rules are written around
    assert 'style="margin-bottom:.85rem"' in html[:html.index('id="fleet"')], (
        "#banners lost the inline bottom margin that is the banner → fleet gap, and today the "
        "only thing spacing the page head from the block")
    after_strip = html[html.index('id="strip"'):]
    assert after_strip.count('style="margin-top:.85rem"') == 3, \
        "a section below the strip lost the inline gap the strip's rule hands off to"


# ---- the `/llm` gufo slot grid (phase 07 task 04) -------------------------
#
# `llm_monitor`'s slot cards (`index.html` ~L1179), rebuilt against the capture instead of a
# memory: one keyed card per gufo slot, every cell naming **one** key of
# `tests/fixtures/slots_gufo.json`. Two things are pinned below, because they are the two ways
# this component failed before: a card that reads a key the server does not publish (dashes
# forever), and a card that is rebuilt every poll so a busy slot flickers in front of you.

#: The keys a slot card reads, and where they live: `field` (and its optional `sub` /
#: `ratioAgainst` partners) index the row, or its first `next_token` entry when `path` says so.
SLOT_ROW_PATHS = ("field", "sub", "ratioAgainst")


def _slot_table(js: str) -> list[dict[str, str | None]]:
    """The served `SLOT_FIELDS` table, one dict per printed cell."""
    body = _code(js)
    start = body.index("const SLOT_FIELDS = [")
    table = body[start:body.index("\n];", start)]
    cells: list[dict[str, str | None]] = []
    for chunk in table.split("{ key: '")[1:]:
        cell: dict[str, str | None] = {"key": chunk.split("'")[0]}
        for option in (*SLOT_ROW_PATHS, "path"):
            found = re.search(rf"{option}: '([a-z_0-9]+)'", chunk)
            cell[option] = found.group(1) if found else None
        cells.append(cell)
    return cells


def _slot_js(js: str) -> str:
    """The slot grid's whole code path, comments out: `slotValue()` to the end of the block."""
    body = _code(js)
    return body[body.index("function slotValue("):body.index("function makeCharts(")]


def _slot_markup(js: str) -> str:
    """Just `slotSection()` — the markup the grid, its label and its empty states are built from."""
    body = _code(js)
    return body[body.index("function slotSection("):body.index("function renderPanel(")]


def test_llm_gufo_panel_holds_the_slot_grid_under_its_label(client) -> None:
    """`sessions (GET /slots)`, then the keyed grid, then the note about what it cannot contain.

    The label is `llm_monitor`'s, the grid ships `hidden` (the empty state is a sentence, never
    a card of nothing), and the note stays because a queued (deferred) request is not in
    `/slots` at all — without that line an idle grid reads as "nothing waiting".
    """
    js = client.get("/static/page-llm.js").text
    markup = _slot_markup(js)
    assert "sessions (GET /slots)" in markup, "/llm lost the slot grid's label"
    # label, grid, empty state, note — in that order, and the grid and the empty state both
    # ship hidden so nothing paints before the payload says which of them is true
    order = ['class="section-label" data-slots-label', "sessions (GET /slots)",
             '<div class="slots" data-slots role="list" hidden>',
             'class="slots-empty" data-slots-empty hidden',
             'class="slots-note" data-slots-note hidden']
    position = -1
    for needle in order:
        found = markup.index(needle)
        assert found > position, f"`{needle}` is out of order in the slot section"
        position = found
    assert "queued (deferred) requests are not in /slots" in js, "the queued-request note is gone"
    assert "renderSlotGrid(card, enginePayload)" in js, "nothing draws the grid any more"
    # the label is a heading and the grid a list: a screen reader gets the block's name and
    # its item count, which a stack of divs does not say
    assert '<h4 class="section-label" data-slots-label>' in markup, \
        "the slot section's label stopped being a heading"
    assert 'data-slots role="list"' in markup, "the grid lost its list semantics"
    # the grid's own markup: a keyed card, the state pill, and one dd per printed cell
    card = js[js.index("function slotCard("):js.index("function slotSub(")]
    assert "setAttribute('role', 'listitem')" in card, "the slot cards left the list"
    assert 'data-slot-cell="${cell.key}"' in card, "the card cells are not table-driven"
    assert 'data-pill' in card and 'data-mark' in card, "the card lost its state pill or glyph"


def test_llm_slot_grid_style_is_a_marker_and_not_a_verdict(client) -> None:
    """A busy slot is a border, a glyph and a word — `severity.py` rates no slot.

    Phase 06 settled this argument for GPU utilisation on an LLM server: a slot generating
    tokens is the job, so the accent colour says *this is the live one* and no `--ok/--warn/
    --fail` token appears anywhere in the section. The glyph (`○`/`●`) and the pill's word mean
    the marker survives monochrome, which is the battery glyph's rule applied here.
    """
    css = client.get("/static/dash.css").text
    section = _css_section(css, "engine slot grid")
    for selector in (".slots {", ".slot {", ".slot.busy", ".slot-top", ".slot-id",
                     ".slot-model", ".slot dt", ".slot dd", ".slots-empty", ".slots-note",
                     ".section-label"):
        assert selector in section, f"dash.css lost the {selector} rule"
    assert "var(--accent)" in section, "the busy marker stopped using the non-verdict accent"
    for token in ("var(--ok)", "var(--warn)", "var(--fail)"):
        assert token not in section, f"the slot grid coloured a state with {token}"
    js = client.get("/static/page-llm.js").text
    assert "'\\u25cf'" in js or "'●'" in js, "the busy glyph left the card"
    assert "processing" in _slot_js(js), "the pill stopped saying the state in a word"


def test_llm_slot_cells_each_name_one_key_the_capture_publishes(client) -> None:
    """Every printed cell traces to a key of `tests/fixtures/slots_gufo.json`.

    One `field` per cell and no `a ?? b`: the deleted table's `slot.n_prompt ??
    slot.prompt_tokens` guessing is what made it print dashes and then plausible noise. A key
    the capture does not have fails here, and the alias the capture answers beside `id_task`
    must not appear in the page at all — the contract names the canonical one.
    """
    # comments out: this test bans names the prose is allowed to explain
    js = _code(client.get("/static/page-llm.js").text)
    cells = _slot_table(js)
    assert cells, "the slot grid has no cell table to read"
    assert [cell["key"] for cell in cells] == ["req", "prompt", "cache", "generated",
                                               "remain", "ctx"], \
        "the slot card's cell set changed without the capture"
    for cell in cells:
        assert cell["field"], f"the {cell['key']} cell names no row key"

    rows = load_slots_capture()
    assert rows, "the capture is empty, so this test would prove nothing"
    for cell in cells:
        for option in SLOT_ROW_PATHS:
            key = cell[option]
            if key is None:
                continue
            in_next = cell["path"] == "next_token"
            required = REQUIRED_NEXT_TOKEN_FIELDS if in_next else REQUIRED_ROW_FIELDS
            optional = OPTIONAL_NEXT_TOKEN_FIELDS if in_next else OPTIONAL_ROW_FIELDS
            assert key in required or key in optional, (
                f"the {cell['key']} cell reads {key!r}, which no contract table declares — the "
                "page would be reading a field nobody pinned")
            for row in rows:
                source = row["next_token"][0] if in_next else row
                if key in required:
                    assert key in source, (
                        f"the {cell['key']} cell reads {key!r}, which "
                        f"{'next_token[0]' if in_next else 'the row'} does not publish — this is "
                        "how the deleted table rendered dashes")
                elif key in source:   # optional: `prob` is on no captured row, and that is legal
                    assert isinstance(source[key], (int, float)), (
                        f"{key!r} is {source[key]!r}, which the cell cannot format")

    assert cells[0]["field"] == CANONICAL_TASK_ID_FIELD, \
        "the request cell stopped reading the canonical task id"
    for alias in TASK_ID_ALIASES:
        assert alias not in js, f"page-llm.js renders the {alias} alias the contract does not name"
    # the old table's invented names stay invented, and so does its per-slot speed
    for gone in ("n_predict", "decode_per_second", "cache_usable", "n_ctx_used"):
        assert gone not in js, f"page-llm.js reads the invented {gone} again"


def test_llm_slot_card_prints_no_speed_it_cannot_measure(client) -> None:
    """No per-slot speed cell: the capture publishes no per-slot rate key.

    `llm_monitor`'s grid has one, and so did the deleted table (`decode_per_second`) — which is
    why it was dashes. A page-side Δn_decoded/Δt would be a measurement with no estimator, no
    `Δ<window>` label and no `source` string, i.e. rule 2 with a confident number printed on it,
    so the number stays on the engine's strip card and panel, where `rates.py` owns it.
    """
    js = _code(client.get("/static/page-llm.js").text)
    assert not [cell for cell in _slot_table(js)
                if cell["key"] in {"speed", "tok_s", "decode"}], "a slot cell grew a rate"
    assert "decode_per_second" not in js


def test_llm_slot_sentinels_print_a_word_or_na_never_a_negative_number(client) -> None:
    """`-1` is llama.cpp's "nothing in this slot", and it never becomes a countdown.

    An idle slot answers `id_task: -1` and `next_token[0].n_remain: -1` (both in the capture).
    The request cell says `idle` in a word; the remaining cell prints `n/a`. Neither prints a
    negative number, and neither prints the `0` that would read as "one token from done".
    """
    body = _slot_js(client.get("/static/page-llm.js").text)
    assert "value < 0 ? 'idle'" in body, "the request cell prints the -1 sentinel again"
    assert "value >= 0 ? value : null" in body, "the remaining cell prints the -1 sentinel"


def test_llm_slot_card_header_reads_only_fields_the_contract_declares(client) -> None:
    """The card top prints `model`, `speculative`, `id` and the state pair — and nothing else.

    `id` keys the card (escaped once at build time), `is_processing` is the authoritative pill,
    `state` labels a number the boolean cannot express, and `model` + `speculative` are the
    footnote beside them. Each is declared in a contract table, so a rename fails there. The
    user-content field a busy row carries (`prompt`) is the one key this page must never read.
    """
    js = client.get("/static/page-llm.js").text
    header = js[js.index("function renderSlotCard("):js.index("function renderSlotGrid(")]
    read = {"is_processing", "state", "model", "speculative"}
    for key in read:
        assert f"row.{key}" in header, f"the slot card header stopped reading {key}"
    declared = set(REQUIRED_ROW_FIELDS) | set(OPTIONAL_ROW_FIELDS)
    assert read <= declared, "the header reads a field no contract table declares"
    for field in USER_CONTENT_FIELDS:
        assert field not in header, f"the slot card prints the user's {field}"
    assert "escapeHtml(id)" in js, "the slot id reached the markup unescaped"


def test_llm_slot_cards_are_keyed_created_once_and_patched_in_place(client) -> None:
    """A busy slot does not get rebuilt every poll — and a slot that leaves loses its card.

    `appendChild` of the existing node keeps DOM order == slot order; everything else is a text
    patch, so a poll cannot flicker a card or re-announce it to assistive tech for a difference
    of a few tokens. An engine that leaves the payload loses its card map with its panel, or the
    refs of removed nodes would be re-appended when it came back.
    """
    js = client.get("/static/page-llm.js").text
    body = _slot_js(js)
    assert "state.slots.get(enginePayload.engine)" in body, "the grid stopped keying its cards"
    assert "if (!refs) {" in body and "refs = slotCard(id)" in body
    assert "grid.appendChild(refs.root)" in body, "slot order is no longer kept by moving nodes"
    assert "byId.delete(id)" in body, "a slot that left keeps its card forever"
    assert "byId.forEach((refs) => refs.root.remove())" in body, \
        "the empty state left cards on the page"
    assert "setTxt(box.value" in body, "the cell values stopped being patched in place"
    assert "innerHTML" not in body.split("function renderSlotCard(")[1], \
        "a card is rebuilt from markup on a poll"
    prune = js[js.index("function pruneEngines("):js.index("/* ---- the gufo slot grid")]
    assert "state.slots.delete(engine)" in prune, "a pruned engine kept its slot cards"


def test_llm_slot_grid_says_why_there_are_no_rows(client) -> None:
    """Two honest empty states, and neither of them is a card or a 0-count claim.

    `/slots` did not answer → the API's own `sessions.detail` sentence (the same words the
    strip's session row carries). It answered with no rows → "engine reports 0 slots", which is
    a fact about that answer. `sessions.source` is the gate that tells the two apart.
    """
    body = _slot_js(client.get("/static/page-llm.js").text)
    assert "Boolean(sessions.source)" in body, "the grid cannot tell no-answer from no-rows"
    assert "engine reports 0 slots" in body
    assert "sessions.detail ||" in body, "the no-answer state lost the API's own sentence"
    assert "no /slots answer from this engine" in body, "the no-answer state can print undefined"


def test_llm_vllm_panel_says_there_is_no_per_slot_json(client) -> None:
    """vLLM gets one line and no grid — no fake rows for a server that cannot answer.

    `sources/llm.py`'s `_sessions()` publishes counts for vLLM and says so in `detail`; the
    panel turns that into the `llm_monitor` line, with the API's sentence as the tooltip. The
    gate is the engine's name (`SLOT_ENGINES`), not `sessions.list.length`, so an engine that
    has not answered yet still shows its label and the honest empty sentence.
    """
    js = client.get("/static/page-llm.js").text
    markup = _slot_markup(js)
    branch = markup.split("if (SLOT_ENGINES.indexOf(engine) < 0) {")[1].split("}")[0]
    assert 'class="slots-note" data-slots-note' in branch, "the vLLM line lost its element"
    assert "NO_SLOT_JSON" in branch and "vLLM exposes no per-slot JSON" in js
    assert '<div class="slots"' not in branch, "the vLLM panel grew a grid it cannot fill"
    body = _slot_js(js)
    assert body.startswith("function slotValue("), "the grid's code path moved"
    assert "if (!grid) {" in body, "renderSlotGrid no longer leaves a panel with no grid alone"
    assert "note.title = enginePayload.sessions.detail" in body, \
        "the vLLM line stopped carrying the API's own words"


def test_the_captured_slot_rows_fill_the_cells_the_grid_prints(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """The capture, through the API, into the keys the served cell table reads.

    The fixture rows are injected as a live job payload (the `/slots` passthrough verbatim), so
    this is the render path's input as the browser would receive it: `sessions.source` set (the
    grid's gate), every row present, and every key `SLOT_FIELDS` names resolvable in it. A
    rename in `sources/llm.py` or in gufo fails here rather than leaving a card of `n/a`s.
    """
    rows = load_slots_capture()
    with build_client(tmp_path, monkeypatch, gufo_url=DEAD_URL,
                      vllm_url=DEAD_URL) as test_client:
        hub = test_client.app.state.ctx.hub  # type: ignore[attr-defined]
        hub.jobs["llm:gufo"].state.payload = {
            "engine": "gufo", "metrics": {"requests_processing": {"value": 1.0}},
            "sessions": {"active": 1, "list": rows, "source": "gufo /slots", "detail": None},
        }
        engines = test_client.get("/api/llm/snapshot").json()["engines"]
        gufo = next(row for row in engines if row["engine"] == "gufo")
        sessions = gufo["sessions"]
        assert sessions["source"] == "gufo /slots", "the grid's gate is gone from the payload"
        assert sessions["list"] == rows, "the rows are no longer the passthrough the grid reads"

        cells = _slot_table(test_client.get("/static/page-llm.js").text)
        for cell in cells:
            for option in SLOT_ROW_PATHS:
                key = cell[option]
                if key is None:
                    continue
                in_next = cell["path"] == "next_token"
                required = REQUIRED_NEXT_TOKEN_FIELDS if in_next else REQUIRED_ROW_FIELDS
                for row in sessions["list"]:
                    source = row["next_token"][0] if in_next else row
                    if key not in required and key not in source:
                        continue        # an optional sub-line this build does not publish
                    value = source[key]
                    assert isinstance(value, (int, float)) and not isinstance(value, bool), (
                        f"the {cell['key']} cell reads {key!r} = {value!r}, which the number "
                        "formatter cannot print")


def test_llm_charts_are_secondary_and_named(client) -> None:
    """The four trend charts stay, at half height, *below* the engine panels, each named.

    Half of the old 165px and moved after `#engines` is the "cells read first" decision;
    every `LineChart` gets an `ariaLabel` because the legend is a sibling that labels
    nothing (`/system` did this in phase 03, `/llm` never had).
    """
    html = _code(client.get("/llm").text)
    assert html.index('id="engines"') < html.index('id="chart-decode"'), \
        "the charts are back on top of the engine panels"
    for chart in ("chart-decode", "chart-prompt", "chart-kv", "chart-queue"):
        assert f'id="{chart}"' in html, f"/llm lost the {chart} chart"
    js = client.get("/static/page-llm.js").text
    assert "height: 110" in js and "height: 165" not in js
    charts = js[js.index("function makeCharts("):js.index("function pointsFor(")]
    assert charts.count("ariaLabel:") == 4, "an /llm chart lost its accessible name"


def test_llm_engine_panels_are_not_stretched_to_their_tallest_sibling(client) -> None:
    """A 5-row gufo panel beside a 7-row vLLM panel keeps its own height.

    Found while comparing against `llm_monitor`: the shorter engine card grew 172 px of
    blank card, and a blank panel reads as "no data" — the exact misreading the unconfigured
    rules exist to prevent. Pinned on the served markup so the `.grid.items-start` rule in
    `dash.css` cannot silently become dead CSS (and the void cannot silently come back).
    """
    html = _code(client.get("/llm").text)
    engines_div = html[html.index('<div class="grid'):html.index('id="engines"') + 40]
    assert "items-start" in engines_div, "the engine grid stretches its cards again"
    css = client.get("/static/dash.css").text
    assert ".grid.items-start" in css, "the rule the engine grid relies on is gone"


def test_overview_is_exactly_two_panels(client) -> None:
    """The landing page answers one question: what is wrong, and what is the fleet doing.

    Asserted on the served bytes because there is no JS test runner (a locked anchor):
    the summary cards and the raw event feed are what made this page busy, and once a
    panel is gone a browser is the only thing that would notice its return.
    """
    html = client.get("/").text
    assert html.count("<section") == 2, "the overview grew a third panel"
    assert 'id="alerts"' in html and 'id="alerts-clear"' in html
    assert 'aria-live="polite"' in html
    assert 'id="fleet-table"' in html
    for gone in ("sys-cpu", "sys-mem", "sys-disk", "sys-gpus", "llm-decode", "llm-kv",
                 "ups-list", 'id="events"'):
        assert gone not in html, f"the overview still renders {gone}"
    # the header's source dots are chrome owned by app.js, not the deleted card dots
    assert 'id="dot-system"' not in html and 'id="nav-status"' in html


def test_overview_alert_rows_link_to_the_dashboard_that_explains_them(client) -> None:
    """Every alert carries the `href` its row turns into a link; the page invents none."""
    page_js = client.get("/static/page-index.js").text
    assert "alert.href" in page_js
    css = client.get("/static/dash.css").text
    for selector in ("ul.alerts li.ok .src", "ul.alerts li.warn .src", "ul.alerts li.fail .src",
                     "table.data td.warn", "table.data td.fail"):
        assert selector in css, f"dash.css lost {selector}"
    # the swap that puts a live problem above the fleet table
    assert 'data-state="alerting"' in css


def test_overview_dims_the_fleet_row_of_a_host_that_stopped_answering(client) -> None:
    """A dead host keeps its last good numbers, so the row has to say they are stale.

    `AGENTS.md` invariant 4: keep the payload and mark it stale, never zero it. The
    overview's table is the one place those last good numbers still print, so it reads the
    per-source verdicts `/api/summary` sends (`system.states`) and applies the shared
    `.stale` class the other pages already use — no new palette, no JS threshold.
    """
    page_js = client.get("/static/page-index.js").text
    assert "system.states" in page_js, "the fleet table stopped reading reachability"
    assert 'class="stale"' in page_js
    assert ".stale" in client.get("/static/dash.css").text


# Which script owns which page, for the orphan check below. `charts.js` and `app.js` are
# loaded by every page, so an id either page code or shared chrome may read.
PAGE_SCRIPTS = {
    "/": "page-index.js",
    "/system": "page-system.js",
    "/disks": "page-disks.js",
    "/llm": "page-llm.js",
    "/ups": "page-ups.js",
    # `/settings` is audited like a dashboard even though it is not one: an id nothing reads is
    # dead markup whatever page it sits on, and this page has five new ones.
    SETTINGS_PAGE: "page-settings.js",
    # `/certs` too (phase 15 task 05): an authority panel and an agents table are markup, and
    # every id in them is written by this page's own script.
    CERTS_PAGE: "page-certs.js",
}
# `/login` is deliberately **not** in this table even though it is audited (phase 11): a
# signed-in client asking for it gets a 303 to the dashboard, so this helper's own
# redirect-following `get` would audit `/`'s markup and call it `/login`. The login page's
# orphan-`id`, CDN and masthead checks live in `tests/test_auth_api.py`, fetched unsigned, and
# `/static/page-login.js` is in `ASSETS` above.

SHARED_SCRIPTS = ("app.js", "charts.js")


def test_no_page_carries_an_id_nothing_reads(client) -> None:
    """An id no script queries, no stylesheet styles and no attribute points at is dead markup.

    The summary cards were retired this way — a `<span id="sys-cpu">` left behind after its
    writer was deleted is the same mistake in slower motion. Asserted on served bytes: the
    browser console is otherwise the only thing that would notice.
    """
    scripts = {name: client.get(f"/static/{name}").text for name in
               (*SHARED_SCRIPTS, *PAGE_SCRIPTS.values(), "dash.css")}
    for path, own_script in PAGE_SCRIPTS.items():
        html = _code(client.get(path).text)
        corpus = "".join(_code(scripts[name])
                         for name in (*SHARED_SCRIPTS, own_script, "dash.css"))
        # ids the markup uses itself: labels, targets, `<label for>`
        anchors = set(re.findall(
            r'(?:aria-labelledby|aria-describedby|aria-controls|for)="([^"]+)"', html))
        for element_id in re.findall(r'id="([^"]+)"', html):
            quoted = (f'"{element_id}"' in corpus or f"'{element_id}'" in corpus
                      or f"#{element_id}" in corpus or element_id in anchors)
            assert quoted, f"{path} has id=\"{element_id}\" that nothing reads"


# ---- the flavour-text audit (phase 08 task 02) ----------------------------
#
# `TODO.md:7`: "Get rid of most of the flavor text and add a note to AGENTS.md to not add it
# unless necessary. It just comes off as LLM generated slop, not helpful information." The
# test is one question per string — *would the operator act differently without it?* — and
# the answer decided the deletion. Copy that explains how the app builds its numbers is not
# helpful information; a provenance tag, a measured Δ window, and the sentence beside an
# empty panel are. `AGENTS.md` → *UI conventions* now carries the rule; the pins below are
# what stop the deleted sentences crawling back, because a screenshot only shows them once
# somebody already knows to look.

#: Fragments deleted from the served pages. The first two are the lines the operator quoted.
DELETED_FLAVOUR = (
    # the overview's footer
    "every number is scraped from the box",
    "Sources the operator never configured are not problems",
    # /system's "Per host" sub-line and its footer
    "agent-reported values",
    "each panel's charts cover only that host",
    "numbers are measured, not inferred",
    # /llm's footer, the one half-sentence of it that lived in the script too
    "each throughput number carries its provenance",
    "rates over the Δ window in each tag",
    "a server you do not run",
    # /ups's footer and its empty state
    "commands are the only write path in this app",
    "The dashboard speaks the NUT protocol",
    # the three event feeds' header captions, all duplicated by an empty-state sentence
    "unreachable / reachable / reboots",
    "engine up / down",
    "state changes, self-test results, commands sent",
)


@pytest.mark.parametrize("fragment", DELETED_FLAVOUR)
def test_no_page_narrates_its_own_pipeline(client, fragment: str) -> None:
    """The deleted copy is gone from every served byte, markup and script alike.

    Asserted across all four pages and all five scripts rather than the file it came from:
    the same sentence migrating into another page's card is the same slop, and a pin that
    only guards its original file would let that through.
    """
    for path in (*MARKUP_PAGES, *ASSETS):
        body = client.get(path).text
        assert fragment not in body, f"{path} narrates the app again: {fragment!r}"


def test_pages_leave_no_empty_narration_container(client) -> None:
    """A deleted sub-line removes its container, not just its words.

    An empty `<span class="sub">` is markup that reserves a line for nothing — the page head
    renders a gap where the sentence used to be. Elements the scripts fill (`#sub`,
    `#alerts-count`) carry an `id` and are not in this category.
    """
    for path in MARKUP_PAGES:
        html = _code(client.get(path).text)
        for cls in ("sub", "faint", "mono"):
            assert f'<span class="{cls}"></span>' not in html, \
                f"{path} keeps an empty .{cls} container"


def test_the_copy_the_operator_acts_on_survives_the_audit(client) -> None:
    """The other half of the deletion: functional copy stays.

    Stripping flavour must not become stripping information. Every string here answers a
    question the operator is asking while looking at the page — why is this panel empty,
    is this number a measurement, is this battery real, is this host's data last-good —
    and each one is the reason the audit deletes sentences and not labels.
    """
    pages = {path: client.get(path).text for path in PAGES}
    scripts = {name: client.get(f"/static/{name}").text for name in PAGE_SCRIPTS.values()}

    # an empty panel says why, in terms the operator can act on
    assert "No hosts configured" in pages["/"]
    assert "HOST_TARGETS" in pages["/system"]
    # …including the fourth page's: a `n/a` drive card is only actionable if the page names
    # the two things that make SMART readable (the binary and the device-read grant).
    assert "smartmontools" in pages["/disks"] + scripts["page-disks.js"]
    assert "disk group" in scripts["page-disks.js"]
    assert "No engines configured" in pages["/llm"]
    assert "No UPS reporting" in pages["/ups"]
    assert "instcmds" in pages["/ups"], "the UPS setup note stopped naming the grant that matters"
    assert "3493" in pages["/ups"], "the page stopped warning that upsd's port is not always 3493"
    # …and the setup copy names the grant NUT actually checks. `README.md` is explicit: a
    # dashboard user gets `instcmds`, never `actions = -`, so a page that told the operator
    # to write that was sending them to fix the wrong line in `upsd.users`.
    assert "actions = -" not in pages["/ups"] + scripts["page-ups.js"] + scripts["page-index.js"]
    assert "instcmds" in scripts["page-ups.js"] and "instcmds" in scripts["page-index.js"]

    # a Δ label is a measurement, and the rate's provenance travels with the rate
    assert "windowLabel(" in scripts["page-system.js"]
    assert "Δ" in scripts["page-llm.js"] and "function provenance(" in scripts["page-llm.js"]
    assert "at the current load" in scripts["page-ups.js"]

    # modelled data is labelled, and so is a feed that cannot contain what you are hunting
    assert "SIMULATED" in scripts["page-index.js"] and "SIMULATED" in scripts["page-ups.js"]
    assert "queued (deferred) requests are not in /slots" in scripts["page-llm.js"]
    assert "Last good values" in scripts["page-index.js"]


def test_api_responses_are_not_cacheable(client) -> None:
    for path in ("/api/config", "/api/health", "/api/summary"):
        assert "no-store" in client.get(path).headers.get("cache-control", "")


# ---- history -------------------------------------------------------------- #

def test_history_returns_seeded_samples(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    db = str(tmp_path / "hist.sqlite3")
    store = SampleStore(db)
    now = time.time()
    for i in range(30):
        store.add("host", "driveripper", "cpu.usage_pct", 10.0 + i, ts=now - 300 + i)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2,
                              host_targets=(Target("driveripper", DEAD_URL),)), store)
    with TestClient(app) as client:
        sign_in(client)
        body = client.get("/api/history", params={"source": "host", "host": "driveripper",
                                                  "metric": "cpu.usage_pct", "range": "15m"})
        assert response_ok(body)
        points = body.json()["points"]
        assert len(points) >= 25
        assert points[-1]["value"] == pytest.approx(39.0)
    store.close()


def test_history_rejects_an_unknown_range(client) -> None:
    response = client.get("/api/history", params={"source": "host", "host": "h",
                                                  "metric": "m", "range": "banana"})
    assert response.status_code == 400


def test_history_requires_the_series_coordinates(client) -> None:
    assert client.get("/api/history").status_code == 422


@pytest.mark.parametrize(("raw", "seconds"), [
    *[(key, float(seconds)) for key, seconds in RANGE_SECONDS.items()],
    ("45s", 45.0), ("13h", 46_800.0), ("7200", 7_200.0), ("  2D  ", 172_800.0),
    (None, 3_600.0), ("", 3_600.0),
])
def test_parse_range_reads_every_window_the_ui_offers(raw: Any, seconds: float) -> None:
    """Every chip key (5m…90d), any `<n><s|m|h|d>`, raw seconds, and the 1h default.

    `parse_range` is the only thing between a typo'd query string and a chart of the wrong
    window, and a wrong window is worse than an error: it still looks like data.
    """
    assert parse_range(raw) == seconds


@pytest.mark.parametrize("raw", ["banana", "1w", "h", "-4h", "one"])
def test_parse_range_refuses_a_window_it_cannot_interpret(raw: str) -> None:
    """A 400 that names the value, never a silent fallback to 1h."""
    with pytest.raises(HTTPException) as excinfo:
        parse_range(raw)
    assert excinfo.value.status_code == 400
    assert raw in str(excinfo.value.detail)


# ---- the routes the *other* pages chart from -------------------------------- #
#
# `/` renders two panels now; `/system`, `/llm` and `/ups` still need these, and so does
# anything outside the browser. Retiring overview code must not retire them, so the shapes
# are pinned here rather than discovered by a page three phases from now.

def test_system_history_charts_every_configured_host_in_one_request(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """N hosts x M metrics, one round trip.

    `/system` no longer uses the N-hosts half of this (every chart belongs to one host and
    the page issues one request per host, pinned by
    `test_every_system_chart_is_drawn_inside_its_own_host_panel`); the shape is kept because
    the metric-list half is exactly what the per-host query costs one request with, and
    because the endpoint is a public interface for programmatic consumers.
    """
    with build_client(tmp_path, monkeypatch,
                      host_targets=(Target("driveripper", DEAD_URL),
                                    Target("deskwork", DEAD_URL))) as test_client:
        body = test_client.get("/api/system/history",
                               params={"metrics": "cpu.usage_pct,mem.used_pct",
                                       "range": "1h"}).json()
        assert body["hosts"] == ["driveripper", "deskwork"]
        assert body["range_seconds"] == 3_600.0
        assert len(body["series"]) == 4
        assert {(item["host"], item["metric"]) for item in body["series"]} == {
            ("driveripper", "cpu.usage_pct"), ("driveripper", "mem.used_pct"),
            ("deskwork", "cpu.usage_pct"), ("deskwork", "mem.used_pct")}
        # an explicit `hosts` list narrows it instead of adding to the default
        narrowed = test_client.get("/api/system/history",
                                   params={"metrics": "cpu.usage_pct",
                                           "hosts": "deskwork"}).json()
        assert narrowed["hosts"] == ["deskwork"]


def test_one_request_per_host_answers_every_per_host_chart(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """The exact query `/system` issues per host returns every series that panel draws.

    `page-system.js` sends one request per host carrying the utilisation trio
    (`cpu.usage_pct`, `mem.used_pct`, `disk.used_pct`), both network rates, and one
    `gpu.busy_pct@<index>` per card the payload reported — so a name missing here is a chart
    that silently reads "no samples yet" in the browser, and a renamed series in
    `sources/host.py` fails here rather than in a screenshot. This is the metric-name half of
    the contract; `tests/test_system_contract.py` holds the payload-path half.
    """
    with build_client(tmp_path, monkeypatch,
                      host_targets=(Target("driveripper", DEAD_URL),)) as test_client:
        store = test_client.app.state.ctx.store  # type: ignore[attr-defined]
        now = time.time()
        metrics = ["cpu.usage_pct", "mem.used_pct", "disk.used_pct",
                   "net.rx_bytes_per_s", "net.tx_bytes_per_s", "gpu.busy_pct@0"]
        for metric in metrics:
            store.add("host", "driveripper", metric, 12.5, ts=now - 60)
            store.add("host", "driveripper", metric, 25.0, ts=now - 30)

        body = test_client.get("/api/system/history", params={
            "hosts": "driveripper", "metrics": ",".join(metrics), "range": "1h"}).json()
        assert body["hosts"] == ["driveripper"], "one panel, one host"
        assert [item["metric"] for item in body["series"]] == metrics
        assert [len(item["points"]) for item in body["series"]] == [2] * len(metrics)

        # a second card the host does not have answers empty, never zero and never 404
        gap = test_client.get("/api/system/history",
                              params={"hosts": "driveripper", "metrics": "gpu.busy_pct@1"}).json()
        assert gap["series"][0]["points"] == []


def test_every_history_endpoint_answers_exactly_what_the_per_series_path_did(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """Phase 14 task 02: the batched store door moved the cost of an N x M request, not its answer.

    All four history routes now ask `store.history_many` for the whole batch instead of looping
    `store.history` per pair. That is only safe if the JSON is the same document the loop built,
    so this compares every route against points read straight out of the store with `query()` —
    a third path, in neither the loop nor the batch — and pins the series order the pages parse
    (host-major, metric-minor) plus the exact key set of one series entry.
    """
    with build_client(tmp_path, monkeypatch, simulate=True, nut_host="127.0.0.1",
                      host_targets=(Target("driveripper", DEAD_URL),
                                    Target("deskwork", DEAD_URL)),
                      gufo_url=DEAD_URL) as test_client:
        store = test_client.app.state.ctx.store  # type: ignore[attr-defined]
        now = time.time()
        writes = [
            ("host", "driveripper", "cpu.usage_pct", [1.0, 2.0, 3.0]),
            ("host", "driveripper", "mem.used_pct", [10.0, 20.0]),
            ("host", "deskwork", "cpu.usage_pct", [4.0, 5.0, 6.0]),
            ("host", "deskwork", "mem.used_pct", [30.0]),
            ("disks", "driveripper", "disk.temp_c@nvme0n1", [38.0, 39.0]),
            ("llm", "gufo", "llm.decode_tokens_per_second", [40.0, 45.0]),
            # a UPS name the simulator does not export, so its 5-second poll cannot add rows to
            # the series this assertion is about
            ("ups", "notaserial", "ups.charge_pct", [99.0, 100.0]),
        ]
        for source, host, metric, values in writes:
            store.add_many([Sample(source, host, metric, value, now - (len(values) - index) * 60)
                            for index, value in enumerate(values)])

        def expected(source: str, host: str, metric: str) -> list[dict[str, float]]:
            rows = store.query(source, host, metric, res=RES_RAW, start=now - 3_600.0, tail=True)
            return [{"ts": ts, "value": value} for ts, value in rows]

        routes = [
            ("/api/system/history", {"hosts": "driveripper,deskwork",
                                    "metrics": "cpu.usage_pct,mem.used_pct", "range": "1h"},
             [("host", host, metric) for host in ("driveripper", "deskwork")
              for metric in ("cpu.usage_pct", "mem.used_pct")]),
            ("/api/disks/history", {"hosts": "driveripper",
                                    "metrics": "disk.temp_c@nvme0n1", "range": "1h"},
             [("disks", "driveripper", "disk.temp_c@nvme0n1")]),
            ("/api/llm/history", {"engines": "gufo", "metrics": "decode_tokens_per_second",
                                  "range": "1h"},
             [("llm", "gufo", "llm.decode_tokens_per_second")]),
            ("/api/ups/history", {"ups": "notaserial", "metrics": "ups.charge_pct",
                                  "range": "1h"},
             [("ups", "notaserial", "ups.charge_pct")]),
        ]
        for path, params, pairs in routes:
            body = test_client.get(path, params=params).json()
            assert len(body["series"]) == len(pairs), path
            for series, (source, host, metric) in zip(body["series"], pairs, strict=True):
                assert set(series) == {"source", "host", "metric", "range_seconds", "points"}
                assert (series["source"], series["host"], series["metric"]) == (source, host, metric)
                assert series["range_seconds"] == 3_600.0
                assert series["points"] == expected(source, host, metric), f"{path} {metric}"

        # and an empty answer is still an answer: a name with no rows, in a batch with names that
        # do, comes back as an empty series rather than a missing entry or a 404
        body = test_client.get("/api/system/history", params={
            "hosts": "driveripper", "metrics": "cpu.usage_pct,gpu.busy_pct@7",
            "range": "1h"}).json()
        assert [series["points"] for series in body["series"]] == [expected(
            "host", "driveripper", "cpu.usage_pct"), []]

        # no metric named is no series asked for: the batch door is never opened with an empty
        # list (SQL `IN ()` is a syntax error waiting for that, and 500 is not the answer anyway)
        empty = test_client.get("/api/system/history",
                                params={"hosts": "driveripper", "metrics": ""}).json()
        assert empty["hosts"] == ["driveripper"] and empty["series"] == []
        no_hosts = test_client.get("/api/system/history",
                                   params={"hosts": "", "metrics": "cpu.usage_pct"}).json()
        assert no_hosts["hosts"] == ["driveripper", "deskwork"], "empty means every configured host"
        assert len(no_hosts["series"]) == 2


def test_llm_snapshot_keeps_an_engine_that_never_answered_in_the_list(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """A configured-but-dead engine is listed as unreachable, not dropped (invariant 4)."""
    # a host target too, so the snapshot's job filter has to skip a non-LLM job
    with build_client(tmp_path, monkeypatch, vllm_url=DEAD_URL,
                      host_targets=(Target("driveripper", DEAD_URL),)) as test_client:
        body = test_client.get("/api/llm/snapshot").json()
        assert [engine["engine"] for engine in body["engines"]] == ["vLLM"]
        assert body["engines"][0]["unreachable"] is True
        assert body["fleet"]["engines_total"] == 1
        assert body["fleet"]["engines_live"] == 0
        assert [state["key"] for state in body["states"]] == ["llm:vllm"]


def test_llm_history_charts_both_engines_by_default(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    with build_client(tmp_path, monkeypatch, gufo_url=DEAD_URL,
                      vllm_url=DEAD_URL) as test_client:
        body = test_client.get("/api/llm/history",
                               params={"metrics": "decode_tokens_per_second,kv_cache_usage_ratio",
                                       "range": "15m"}).json()
        assert body["engines"] == ["gufo", "vllm"]
        assert body["range_seconds"] == 900.0
        assert {(item["host"], item["metric"]) for item in body["series"]} == {
            ("gufo", "llm.decode_tokens_per_second"),
            ("gufo", "llm.kv_cache_usage_ratio"),
            ("vllm", "llm.decode_tokens_per_second"),
            ("vllm", "llm.kv_cache_usage_ratio")}


def test_one_batched_llm_history_request_answers_every_cell_series(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """The exact query `/llm` issues per refresh returns every chart *and* sparkline series.

    Phase 04 sends one request carrying the chart trio and the whole spark cell list —
    including the two series the layout required (`tpot_seconds` for the vLLM TPOT row,
    `spec_accept_rate` for the gufo spec row). A name missing here is a cell that reads
    "no history" forever in the browser, which is the dead-cell anti-pattern the phase
    wrote NOTES-chart-set to prevent; a rename in `sources/llm.py` fails here first.
    """
    with build_client(tmp_path, monkeypatch, gufo_url=DEAD_URL,
                      vllm_url=DEAD_URL) as test_client:
        store = test_client.app.state.ctx.store  # type: ignore[attr-defined]
        now = time.time()
        metrics = ["decode_tokens_per_second", "prompt_tokens_per_second",
                   "kv_cache_usage", "requests_running", "requests_waiting",
                   "ttft_seconds", "tpot_seconds", "queue_seconds",
                   "prefix_cache_hit_ratio", "spec_accept_rate"]
        for metric in metrics:
            store.add("llm", "gufo", f"llm.{metric}", 1.5, ts=now - 60)
            store.add("llm", "vllm", f"llm.{metric}", 2.5, ts=now - 30)
        body = test_client.get("/api/llm/history", params={
            "engines": "gufo,vllm", "metrics": ",".join(metrics), "range": "1h"}).json()
        assert body["range_seconds"] == 3_600.0
        by_key = {(item["host"], item["metric"]) for item in body["series"]}
        assert by_key == {(engine, f"llm.{metric}")
                          for engine in ("gufo", "vllm") for metric in metrics}
        points = {(item["host"], item["metric"]): item["points"] for item in body["series"]}
        assert points[("gufo", "llm.spec_accept_rate")][0]["value"] == pytest.approx(1.5)
        assert points[("vllm", "llm.tpot_seconds")][0]["value"] == pytest.approx(2.5)


def test_metrics_endpoint_lists_what_actually_has_history(client) -> None:
    body = client.get("/api/metrics").json()
    assert body["metrics"] == []


# ---- the `/disks` API (phase 09 task 03) ---------------------------------- #
#
# The drive-health surface answers like every other dashboard's: GETs only, the same
# stale/stub semantics for a host that is not answering, the same history mechanism for the
# `disk.*@dev` series, and the same 404-`configured: false` sentence when no agent is
# configured at all — the last one *without dialling*, because "not deployed here" must not
# cost a connect timeout or a red dot (invariant 3).

@pytest.fixture
def disks_client(tmp_path: Path, monkeypatch: pytest.MonkeyPatch,
                 disk_snapshot: Any) -> Iterator[TestClient]:
    """Two hosts configured; one of them answering SMART, through the production parser.

    The payload and the stored samples are what `parse_disks_snapshot` makes of the
    fixture-shaped capture (the agent's whole-disk rows plus the recorded `smartctl` shapes),
    so every path a `/disks` card will read is a path the source really emits. The other host
    keeps its `unreachable` stub, which is the shape a dead agent must keep (invariant 4).
    Both targets point at a dead port, so nothing dials.
    """
    db = str(tmp_path / "disks.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2,
                              host_targets=(Target("driveripper", DEAD_URL),
                                            Target("deskwork", DEAD_URL))), store)
    with TestClient(app) as test_client:
        sign_in(test_client)
        now = time.time()
        snapshot = disk_snapshot("driveripper")
        snapshot["ts"] = now          # "the agent answered just now", so charts are in range
        result = parse_disks_snapshot("driveripper", snapshot, DisksCollector(), now=now)
        store.add_many(result.samples)
        app.state.ctx.hub.jobs["disks:driveripper"].state.payload = result.payload
        yield test_client
    store.close()


@pytest.fixture
def mixed_disks_client(tmp_path: Path, monkeypatch: pytest.MonkeyPatch,
                       disk_snapshot: Any) -> Iterator[TestClient]:
    """Four configured hosts: one per answer an agent can give about `smartctl`, plus a stub.

    Phase 22's visibility gate needs all three arms of `smartctl_available` in **one** fleet,
    because "hidden" only means something against what stays:

    * `driveripper` — every drive read: `smartctl_available: true`
    * `deskwork` — every drive `null` with no error line: `null` (`--no-smart`, or an agent
      predating the SMART pass — it answered, it just cannot say)
    * `gateway` — every drive `null` plus the agent's own "not found" line: `false`, which is
      the one arm that hides a host (`api._disk_visible`)
    * `deadhost` — never answered: the `unreachable` stub, whose flag is `null` by shape

    Each payload is `parse_disks_snapshot`'s own output over the fixture captures, and every
    target points at a dead port, so nothing dials and no poll can overwrite what is set here.
    """
    db = str(tmp_path / "mixed-disks.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2,
                              host_targets=(Target("driveripper", DEAD_URL),
                                            Target("deskwork", DEAD_URL),
                                            Target("gateway", DEAD_URL),
                                            Target("deadhost", DEAD_URL))), store)
    with TestClient(app) as test_client:
        sign_in(test_client)
        now = time.time()
        for name, mode in (("driveripper", "healthy"), ("deskwork", "silent"),
                           ("gateway", "no_binary")):
            snapshot = disk_snapshot(name, mode=mode)
            snapshot["ts"] = now      # "the agent answered just now"
            result = parse_disks_snapshot(name, snapshot, DisksCollector(), now=now)
            app.state.ctx.hub.jobs[f"disks:{name}"].state.payload = result.payload
        yield test_client
    store.close()


#: (`smart` field, severity metric) for the two drive numbers the table rates — the same
#: pair `sources/disks.py:SEVERITY_FIELDS` declares, restated here so a rename that only
#: touches one side fails rather than colouring nothing.
RATED_CELLS: tuple[tuple[str, str], ...] = (
    ("temp_c", "disk.temp_c"),
    ("percentage_used", "disk.percentage_used"),
)


def disk_rows(body: dict[str, Any], host: str = "driveripper") -> list[dict[str, Any]]:
    """The disk rows of one host out of a `/api/disks/snapshot` body."""
    return next(row for row in body["hosts"] if row["name"] == host)["disks"]


def flat_routes(app: Any) -> list[Any]:
    """Every route the app serves, with `include_router()` results flattened to their routes.

    The FastAPI this repo pins keeps an included router as an `_IncludedRouter` wrapper with
    no `path` of its own, so walking `app.routes` alone sees five anonymous objects instead of
    the API surface — and the verb assertion below is only as good as this walk.
    """
    out: list[Any] = []
    for route in app.routes:
        inner = getattr(route, "original_router", None)
        out.extend(inner.routes if inner is not None else [route])
    return out


def series_source(body: dict[str, Any]) -> set[str]:
    """Which sample family a history answer came from: `disks`, never the 10-second `host`."""
    return {series["source"] for series in body["series"]}


def test_disks_snapshot_answers_one_entry_per_host_with_its_physical_disks(
        disks_client) -> None:
    """`GET /api/disks/snapshot` is per host: rows + `smart` + `smartctl_available`.

    "Per host" means per **visible** host since phase 22 — this fleet has no `false` host in
    it, so both stub and answering host are listed; the hidden case is pinned on a fleet that
    has one (`mixed_disks_client`).
    """
    body = disks_client.get("/api/disks/snapshot")
    assert response_ok(body)
    payload = body.json()
    assert [host["name"] for host in payload["hosts"]] == ["deskwork", "driveripper"], (
        "every configured host is a row, in name order, answering or not")
    rows = disk_rows(payload)
    assert rows, "the capture has 16 whole-disk devices, so the page has 16 cards"
    assert all("/" not in row["device"] for row in rows), "a mount leaked into the disk list"
    first = rows[0]
    assert first["path"] == f"/dev/{first['device']}"
    assert set(first) >= {"device", "path", "model", "size_bytes", "rotational",
                          "health", "smart", "severity"}
    assert first["smart"]["power_on_hours"] > 0, "the drive's own counters travel verbatim"
    live = next(host for host in payload["hosts"] if host["name"] == "driveripper")
    assert live["smartctl_available"] is True
    assert live["smart_errors"] == []
    assert live["summary"]["disks"] == len(rows)
    assert "unreachable" not in live, "answering is the absence of the flag, as on /system"
    assert [state["key"] for state in payload["states"]] == ["disks:driveripper",
                                                             "disks:deskwork"], (
        "the page's dots come from the disks jobs, never the system ones")


def test_disks_snapshot_carries_the_verdicts_the_page_will_paint(disks_client) -> None:
    """Colour is in the payload: each row's `severity` is what `severity.classify` says.

    This is the pin that keeps the threshold out of the page — `page-disks.js` reads these
    and never compares a drive temperature to a bound.
    """
    rows = disk_rows(disks_client.get("/api/disks/snapshot").json())
    assert "ok" in {row["severity"]["temp_c"] for row in rows}, "the capture is healthy"
    for row in rows:
        smart = row["smart"] or {}
        assert set(row["severity"]) == {field for field, _metric in RATED_CELLS} | {"health"}
        for field, metric in RATED_CELLS:
            assert row["severity"][field] == classify(metric, smart.get(field)), (
                f"{row['device']}.{field} is coloured by something other than the one table")
    assert not {key for row in rows for key in row["severity"]} & {
        "reallocated_sector_ct", "pending", "uncorrectable", "power_on_hours"}, (
        "a counter is an alarm chip on presence, never a graded cell")


def test_a_configured_host_with_no_payload_yet_is_a_row_of_nas(disks_client) -> None:
    """The stub shape `/api/system/snapshot` hands out, so `n/a` is never a missing row.

    A host in `HOST_TARGETS` that has not answered is still in the fleet (invariants 3 and
    4) with its counts `None` rather than `0`: "unknown" and "no drives" are different
    sentences (rule 2), and the fleet header counts it without summing it.
    """
    payload = disks_client.get("/api/disks/snapshot").json()
    stub = next(host for host in payload["hosts"] if host["name"] == "deskwork")
    assert stub["unreachable"] is True
    assert stub["disks"] == [], "nothing to draw, but the host is still listed"
    assert stub["smartctl_available"] is None, "an agent that never answered says nothing"
    assert stub["smart_errors"] == []
    assert set(stub["summary"]) == {"disks", "with_smart", "health_failed", "alarm_disks"}
    assert all(value is None for value in stub["summary"].values()), "no invented zeros"
    fleet = payload["fleet"]
    assert (fleet["hosts_total"], fleet["hosts_live"]) == (2, 1)
    assert fleet["disks"] == len(disk_rows(payload))


def test_the_disks_fleet_header_is_summed_by_the_api_not_the_page(disks_client) -> None:
    """`fleet` is the header's only arithmetic source, and it carries no verdict."""
    payload = disks_client.get("/api/disks/snapshot").json()
    live = next(host for host in payload["hosts"] if host["name"] == "driveripper")
    fleet = payload["fleet"]
    assert fleet["disks"] == live["summary"]["disks"]
    assert fleet["alarm_disks"] == live["summary"]["alarm_disks"] > 0, (
        "the recorded ATA shape carries reallocated sectors, so the fleet has chips to draw")
    assert "severity" not in fleet, "a count of drives is not a graded number"


# ---- the `/disks` visibility gate (phase 22 task 01) ----------------------- #
#
# `TODO.md:13`: "VMs that don't have smartctl enabled disks should not show up. Gateway
# shouldn't even be a host on the disks page." One predicate (`api._disk_visible`) over the
# three arms of `smartctl_available`, applied to the assembled host list in both endpoints, so
# the page's rows, that block's rows and the fleet sums cannot describe three fleets. The
# source, the store, the `disks:<host>` job and its health record still see every host.

def test_the_disk_visibility_gate_reads_only_the_explicit_false() -> None:
    """Three arms, one hide condition — and the test is `is False`, not falsy.

    `None` means "nobody knows" (an agent predating the SMART pass, `--no-smart`, or a payload
    with no such key at all) and an agent that cannot say is not an agent that said *no*; a
    dead agent's stub stays too, because a machine that stopped answering must never read as
    "never configured" (invariant 3).
    """
    assert _disk_visible({"smartctl_available": True}) is True
    assert _disk_visible({"smartctl_available": None}) is True
    assert _disk_visible({}) is True, "a payload that never said anything is not a 'no'"
    assert _disk_visible({"unreachable": True, "smartctl_available": None}) is True, (
        "a dead agent is not a host without smartmontools")
    assert _disk_visible({"smartctl_available": 0}) is True, (
        "falsy is not the predicate — only the value the agent answered with")
    assert _disk_visible({"smartctl_available": False}) is False


def test_a_host_whose_agent_has_no_smartctl_is_not_a_host_on_the_disks_page(
        mixed_disks_client) -> None:
    """The absent host and the two `unknown` hosts, pinned in the same response.

    gateway's VM answers "`smartctl` not found", so it has no card and no row; deskwork's
    agent cannot say either way and deadhost's never answered, and both keep their dimmed
    `n/a` rows exactly as before this gate existed.
    """
    payload = mixed_disks_client.get("/api/disks/snapshot").json()
    visible = {host["name"]: host for host in payload["hosts"]}
    assert list(visible) == ["deadhost", "deskwork", "driveripper"], (
        "only the host whose agent said 'no smartctl' is gone")
    assert visible["driveripper"]["smartctl_available"] is True
    assert visible["driveripper"]["disks"], "the host that stayed kept every drive row"
    assert visible["deskwork"]["smartctl_available"] is None, (
        "an agent that cannot say is still a card, with its own why-line")
    assert "unreachable" not in visible["deskwork"], "it answered — silently, but it answered"
    assert visible["deadhost"]["unreachable"] is True
    assert visible["deadhost"]["smartctl_available"] is None


def test_the_disks_fleet_header_counts_only_the_hosts_the_page_lists(
        mixed_disks_client) -> None:
    """`hosts_total` is the page's row count, and a hidden host lends it no drives."""
    payload = mixed_disks_client.get("/api/disks/snapshot").json()
    fleet = payload["fleet"]
    rows_by_host = {host["name"]: host["disks"] for host in payload["hosts"]}
    assert fleet["hosts_total"] == len(payload["hosts"]) == 3
    assert fleet["hosts_live"] == 2, "the stub host is counted and never summed"
    assert fleet["disks"] == len(rows_by_host["driveripper"]) + len(rows_by_host["deskwork"]), (
        "the hidden host's `vda` is in no fleet count")
    assert fleet["with_smart"] == len(rows_by_host["driveripper"])
    assert "severity" not in fleet


def test_hiding_a_diskless_host_leaves_its_health_record_and_the_fleet_alone(
        mixed_disks_client) -> None:
    """The gate reads a payload; it does not unwatch the machine.

    `states` still lists `disks:gateway` (the job polls, and healthy is healthy), `/system`
    still lists gateway as a host, and `/api/health` still answers for the job — a box with no
    smartmontools is missing from the **drive** page and from nothing else (invariant 3).
    """
    snapshot = mixed_disks_client.get("/api/disks/snapshot").json()
    summary = mixed_disks_client.get("/api/summary").json()
    assert {state["key"] for state in snapshot["states"]} == {
        "disks:deadhost", "disks:deskwork", "disks:driveripper", "disks:gateway"}
    assert "gateway" in {row["name"] for row in summary["system"]["hosts"]}, (
        "the system page lost a machine over a missing binary")
    health = {row["key"]: row for row in
              mixed_disks_client.get("/api/health").json()["sources"]}
    assert "disks:gateway" in health


def test_summary_and_the_disks_page_hide_the_same_hosts(mixed_disks_client) -> None:
    """One predicate, two endpoints: `/` and `/disks` may not list different machines."""
    body = mixed_disks_client.get("/api/summary").json()
    snapshot = mixed_disks_client.get("/api/disks/snapshot").json()
    disks = body["disks"]
    # the **set**, not the list: `/api/disks/snapshot` sorts by name, `/api/summary` answers
    # rows in hub order and always has
    assert {row["name"] for row in disks["hosts"]} == {
        host["name"] for host in snapshot["hosts"]} == {
        "deadhost", "deskwork", "driveripper"}
    assert disks["fleet"] == snapshot["fleet"], "the header would disagree with the page"
    assert disks["fleet"]["hosts_total"] == 3
    assert disks["enabled"] is True
    assert disks["fleet"]["hosts_total"] != len(body["system"]["hosts"]), (
        "four machines configured, three drive rows — the two numbers are different facts")
    # the rows that stayed carry the shape they always did, `unknown` and all (rule 2)
    rows = {row["name"]: row for row in disks["hosts"]}
    assert rows["deskwork"]["smartctl_available"] is None
    assert rows["deskwork"]["unreachable"] is False
    assert rows["deadhost"]["unreachable"] is True and rows["deadhost"]["disks"] is None


def test_the_disk_visibility_gate_applies_with_only_one_host_configured(
        tmp_path: Path, disk_snapshot: Any) -> None:
    """A fleet of nothing but a `false` host is an empty drive page, not a 404.

    Unconfigured still means "no `HOST_TARGETS`" (a 404 that dials nothing, invariant 3);
    configured-and-hidden answers with an empty list and a zero fleet, which is what the page
    renders as its empty state.
    """
    db = str(tmp_path / "one-hidden-host.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2,
                              host_targets=(Target("gateway", DEAD_URL),)), store)
    with TestClient(app) as test_client:
        sign_in(test_client)
        now = time.time()
        snapshot = disk_snapshot("gateway", mode="no_binary")
        snapshot["ts"] = now
        result = parse_disks_snapshot("gateway", snapshot, DisksCollector(), now=now)
        assert result.payload["smartctl_available"] is False, "the arm this test is about"
        app.state.ctx.hub.jobs["disks:gateway"].state.payload = result.payload
        body = test_client.get("/api/disks/snapshot")
        assert body.status_code == 200, "configured-and-hidden is not unconfigured"
        payload = body.json()
        assert payload["hosts"] == []
        assert payload["fleet"]["hosts_total"] == 0
        assert payload["fleet"]["disks"] == 0
        assert [state["key"] for state in payload["states"]] == ["disks:gateway"]
        summary = test_client.get("/api/summary").json()["disks"]
        assert summary["enabled"] is True
        assert summary["hosts"] == []
        assert summary["fleet"] == payload["fleet"], (
            "an all-hidden fleet must look the same from both endpoints")
    store.close()


def test_the_disks_surface_is_gets_only_and_the_write_stays_the_ups_one(
        disks_client) -> None:
    """Invariant 1: the app writes to an **upstream** from exactly one route."""
    routes = flat_routes(disks_client.app)
    disks = [route for route in routes
             if str(getattr(route, "path", "")).startswith("/api/disks")]
    assert {route.path for route in disks} == {"/api/disks/snapshot", "/api/disks/history"}
    verbs = {verb for route in disks for verb in (getattr(route, "methods", None) or set())}
    assert verbs == {"GET"}, "a write appeared on the drive-health surface"
    for verb in ("POST", "PUT", "PATCH", "DELETE"):
        response = disks_client.request(verb, "/api/disks/snapshot", json={})
        assert response.status_code == 405, f"{verb} /api/disks/snapshot was accepted"
    writes = sorted(str(route.path) for route in routes
                    if "POST" in (getattr(route, "methods", None) or set()))
    # Invariant 1 is about the fleet. The `/auth/` writes create, re-credential, and clear a
    # session in this process; the `/certs/` writes (phase 15) mint, reissue, and revoke a
    # certificate in this process's `meta` table. Neither dials anything — and a revocation's whole
    # effect is that the *next poll* refuses to dial — so they are named here rather than filtered
    # out of sight, because the failure this assertion catches is a POST arriving quietly.
    authority = [path for path in writes if path.startswith("/api/certs/")]
    session = [path for path in writes if path.startswith("/api/auth/")]
    upstream = [path for path in writes
                if not path.startswith(("/api/auth/", "/api/certs/"))]
    assert upstream == ["/api/ups/command"], "one write endpoint, four gates, unchanged"
    assert session == ["/api/auth/login", "/api/auth/logout", "/api/auth/password"]
    assert authority == ["/api/certs/root/rotate", "/api/certs/{name}/revoke",
                         "/api/certs/{name}/rotate"], "the CA surface grew a write nobody named"
    # …and nothing anywhere grew the verbs this app has no use for, session included.
    assert not sorted(path for route in routes
                      for path in [str(route.path)]
                      if set(getattr(route, "methods", None) or ()) & {"PUT", "PATCH", "DELETE"})
    # The session writes are not upstream writes, but they are still the only ones: `/login`
    # is the page, not a POST target, and `/api/auth/status` stays a read.
    pages = sorted(str(route.path) for route in routes
                   if "GET" in (getattr(route, "methods", None) or set())
                   and not str(route.path).startswith("/api/"))
    # `/settings` (phase 11) is a fifth dashboard-shaped **page** and it grew no verb: a page
    # route is a GET, so the write surface this test guards stays the one UPS command.
    assert pages == ["/", "/certs", "/disks", "/llm", "/login", "/settings", "/system",
                     "/ups"]


def test_config_prints_the_disks_cadence_the_page_explains_itself_with(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """A card four minutes old is behaving, not broken — and the interval is the proof.

    `/disks` has no upstream of its own, so `enabled` follows `HOST_TARGETS` and the cadence
    is its own. Both numbers come from config rather than a constant in the page, so changing
    `DISKS_INTERVAL_SECONDS` moves the sentence and the poller together.
    """
    with build_client(tmp_path, monkeypatch, host_targets=(Target("driveripper", DEAD_URL),),
                      disks_interval=120.0, disks_timeout=45.0) as test_client:
        disks = test_client.get("/api/config").json()["disks"]
        assert disks["enabled"] is True
        assert disks["interval_seconds"] == 120.0
        assert disks["timeout_seconds"] == 45.0


def test_disks_snapshot_404s_without_dialling_a_host_that_was_never_configured(
        client, monkeypatch: pytest.MonkeyPatch) -> None:
    """The gate runs before anything that could reach the network (invariant 3).

    Both spies raise, so a route that constructed a client or fetched a snapshot before
    checking `HOST_TARGETS` fails here instead of costing a timeout and a red dot. The hub
    assertion is the structural half: with no targets there is no `disks` job to dial with.
    """
    calls: list[str] = []

    def spy_get(self: Any, url: Any, **kwargs: Any) -> Any:
        calls.append(f"GET {url}")
        raise AssertionError(f"the unconfigured disks route dialled {url}")

    def spy_fetch(*args: Any, **kwargs: Any) -> Any:
        calls.append("fetch_snapshot")
        raise AssertionError("the unconfigured disks route fetched an agent snapshot")

    monkeypatch.setattr(httpx.AsyncClient, "get", spy_get)
    monkeypatch.setattr("dashboards.collectors.fetch_snapshot", spy_fetch)

    response = client.get("/api/disks/snapshot")
    assert response.status_code == 404
    body = response.json()
    assert body["configured"] is False
    assert "HOST_TARGETS" in body["detail"], "the sentence names the fix"
    assert calls == [], "an unconfigured page must not touch the network"
    assert client.app.state.ctx.hub.jobs == {}, (
        "no targets means no disks job, so nothing can age out or go red")


def test_disks_history_serves_the_dev_series_the_page_charts(disks_client) -> None:
    """One request, every series a host's cards could draw, points from the stored samples."""
    rows = disk_rows(disks_client.get("/api/disks/snapshot").json())
    metrics = [f"{base}@{row['device']}" for row in rows for _field, base in SMART_SERIES]
    body = disks_client.get("/api/disks/history", params={
        "hosts": "driveripper", "metrics": ",".join(metrics), "range": "1h"}).json()
    assert body["hosts"] == ["driveripper"], "one host, one panel"
    assert body["range_seconds"] == 3_600.0
    assert [series["metric"] for series in body["series"]] == metrics
    assert series_source(body) == {"disks"}, "the disks family, never the 10-second host one"
    points = {(series["metric"]): series["points"] for series in body["series"]}
    assert points["disk.temp_c@nvme0n1"][0]["value"] == pytest.approx(38.0)
    assert points["disk.power_on_hours@nvme0n1"][0]["value"] == pytest.approx(8_760.0)


def test_disks_history_answers_empty_for_a_series_a_drive_does_not_publish(
        disks_client) -> None:
    """Unknown names are an empty series, not a 404 — the /system and /llm contract.

    The recorded ATA shape reports no `percentage_used`, so that drive's wear plot has
    nothing to draw, and a device name the agent never listed behaves the same way. The card
    asks for every series it could draw and reads `n/a` where there is nothing, instead of
    the request failing.
    """
    rows = disk_rows(disks_client.get("/api/disks/snapshot").json())
    unworn = next(row["device"] for row in rows
                  if (row["smart"] or {}).get("percentage_used") is None)
    body = disks_client.get("/api/disks/history", params={
        "hosts": "driveripper",
        "metrics": f"disk.percentage_used@{unworn},disk.temp_c@nosuchdisk,"
                   "disk.temp_c@nvme0n1",
        "range": "1h"}).json()
    by_metric = {series["metric"]: series["points"] for series in body["series"]}
    assert by_metric[f"disk.percentage_used@{unworn}"] == [], "no measurement, no line"
    assert by_metric["disk.temp_c@nosuchdisk"] == []
    assert by_metric["disk.temp_c@nvme0n1"], "the series that does exist still answers"


def test_disks_history_charts_every_configured_host_in_one_request(disks_client) -> None:
    """With no `hosts` the answer covers every configured agent, dead ones included (empty)."""
    body = disks_client.get("/api/disks/history",
                            params={"metrics": "disk.temp_c@nvme0n1,disk.temp_c@sda",
                                    "range": "24h"}).json()
    assert body["hosts"] == ["driveripper", "deskwork"]
    assert body["range_seconds"] == 86_400.0
    assert {(series["host"], series["metric"]) for series in body["series"]} == {
        ("driveripper", "disk.temp_c@nvme0n1"), ("driveripper", "disk.temp_c@sda"),
        ("deskwork", "disk.temp_c@nvme0n1"), ("deskwork", "disk.temp_c@sda")}
    assert [series for series in body["series"] if series["host"] == "deskwork"], (
        "a host with no history is an empty series, never a missing one")


def test_the_metrics_endpoint_answers_for_the_disks_family(disks_client) -> None:
    """"Why is this chart empty" has an answer per page: /api/metrics?source=disks."""
    body = disks_client.get("/api/metrics", params={"source": "disks"}).json()
    assert "disk.temp_c@nvme0n1" in body["metrics"]
    assert not [name for name in body["metrics"] if not name.startswith("disk.")], (
        "the disks family holds only disk series")
    assert not [name for name in disks_client.get(
        "/api/metrics", params={"source": "host"}).json()["metrics"]
        if name.startswith("disk.temp_c")], "SMART never mixes into the system family"


# ---- the `/disks` page (phase 09 task 04) ---------------------------------- #
#
# The fourth dashboard, asserted the way the other three are: on the served bytes, because a
# JS test runner would be a build step (a locked anchor). What is pinned is not that the page
# exists but that it keeps the four promises the phase wrote down — one card per **physical**
# drive and never one per partition, alarm chips that exist only while a counter is non-zero,
# a host without `smartctl` dimmed rather than reddened, and charts that belong to one host,
# stay collapsed until opened, and cost one history request per host per refresh.

def _disks_js(client: TestClient) -> str:
    return client.get("/static/page-disks.js").text


def test_the_disks_tab_is_in_the_masthead_of_every_page(client) -> None:
    """Four tabs became five, on every page, with exactly one marking itself current.

    The masthead is the app's only "which dashboard do I need" surface since phase 02 deleted
    the overview's table, so a tab missing from one page is a page you cannot get to, and a
    tab marked current on the wrong page is a lie about where you are.
    """
    for path in PAGES:
        html = client.get(path).text
        assert '<a href="/disks"' in html, f"{path}'s nav has no Disks tab"
        assert html.count('aria-current="page"') == 1, f"{path} marks more than one tab current"
        assert f'<a href="{path}" aria-current="page">' in html, f"{path} does not mark itself"
        assert (html.index('href="/system"') < html.index('href="/disks"')
                < html.index('href="/llm"')), "tab order is machine, drive, engine, power"


# ---- the collapsing masthead nav (phase 18) -------------------------------- #
#
# At ≤640px the five tab links leave the bar and come back as a dropdown under it, opened by
# one `☰` button. There is no JS test runner (a locked anchor), so the phase is pinned the way
# every page surface here is: on the served bytes. Three questions, in the order the pieces
# were built — is the button on every tabbed page and on no others, does the stylesheet still
# hide it above the breakpoint, and do the stylesheet and the binding still agree on the
# breakpoint itself? That last one is the only failure mode no browser check catches: a number
# that drifts in one file opens a menu into a hidden nav on the operator's phone.

#: The attributes that make `#nav-toggle` a button and not a mystery glyph: it is not a form
#: control (`type`), it says what it toggles (`aria-controls`), it says what state it is in
#: (`aria-expanded`, which `app.js` keeps honest), and its only content is a `☰`.
NAV_TOGGLE_ATTRS = ('class="ghost nav-toggle"', 'type="button"', 'aria-expanded="false"',
                    'aria-controls="nav-tabs"', 'aria-label="Toggle navigation"')


def _masthead(html: str) -> str:
    """The served page's own masthead — the block the toggle and the nav have to live in.

    Slicing rather than searching the whole document is the point: a button in the footer would
    satisfy `id="nav-toggle" in html` and anchor to nothing, because the dropdown's
    `top: 100%` resolves against `.masthead`.
    """
    start = html.index('<header class="masthead"')
    return html[start:html.index("</header>", start)]


def test_the_nav_toggle_is_in_the_masthead_of_every_tabbed_page(client) -> None:
    """Seven pages, one identical button, and the nav it controls still carrying five tabs.

    The dropdown is the only way to change dashboard on a phone, so a page missing the button is
    a page you can enter and leave the tab bar on, and a page whose nav lost its `id` is a button
    that toggles nothing. Pinned on all seven (`MARKUP_PAGES`) rather than on `PAGES` because the
    two admin pages have the same masthead and therefore the same contract.
    """
    for path in MARKUP_PAGES:
        header = _masthead(client.get(path).text)
        button = re.search(r'<button[^>]*id="nav-toggle"[^>]*>', header, re.S)
        assert button, f"{path}'s masthead has no #nav-toggle button"
        for attr in NAV_TOGGLE_ATTRS:
            assert attr in button.group(0), f"{path}'s nav toggle is missing {attr}"
        assert header.count('id="nav-toggle"') == 1, f"{path} has more than one nav toggle"

        # The nav is the menu: the id the button names, and all five dashboards inside it.
        assert '<nav class="tabs" id="nav-tabs" aria-label="Dashboards">' in header, \
            f"{path}'s tab nav has no #nav-tabs for the toggle to control"
        nav = header[header.index('id="nav-tabs"'):header.index("</nav>",
                                                                header.index('id="nav-tabs"'))]
        for tab in PAGES:
            assert f'href="{tab}"' in nav, f"{path} collapsed a nav that lost the {tab} tab"

        # Order inside the masthead: brand, toggle, nav — and the cluster after them, because
        # the ≤640px block right-aligns the button and wraps the cluster onto its own row.
        assert (header.index('id="nav-toggle"') < header.index('id="nav-tabs"')
                < header.index('class="masthead-right"')), \
            f"{path} put the toggle or the nav outside the brand → tabs → cluster row"


def test_the_login_page_carries_no_nav_and_no_toggle(tmp_path: Path) -> None:
    """`/login` is brand link + theme toggle, and the shared binding must be inert there.

    No `client` fixture, and that is the whole shape of the test: the signed-in one cannot see
    this page at all (a signed-in `GET /login` is a `303` to the dashboard, and following it
    audits `/`'s markup under the name `/login`), which is the same redirect trap
    `tests/test_auth_api.py::test_the_login_page_carries_no_id_nothing_reads_and_no_dashboard_nav`
    documents for the orphan-`id` audit.

    Every tab on this page bounces straight back to it, so the page renders no tabs at all; a
    stray hamburger would be a control that opens a menu of redirects, and the `640px` block
    would reveal it. The last assertion is the other half of the contract: `app.js` still loads
    here, which is only safe because `if (navToggle && appNav)` no-ops without the elements.
    """
    db = str(tmp_path / "login-nav.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2), store)
    try:
        with TestClient(app) as anon:
            response = anon.get("/login")
            assert response.status_code == 200, \
                "a signed-out /login must be the form, not a bounce"
            html = response.text
    finally:
        store.close()

    for absent in ('id="nav-toggle"', 'id="nav-tabs"', 'class="tabs"',
                   'aria-controls="nav-tabs"', 'aria-label="Dashboards"'):
        assert absent not in html, f"/login renders the collapsed nav's {absent}"
    assert '<a class="brand" href="/">' in html and 'id="theme-toggle"' in html, \
        "/login lost the two pieces of chrome that do belong on it"
    assert 'src="/static/app.js"' in html, (
        "/login stopped loading the shared chrome whose guard is its no-toggle contract")


# ---- the fleet badges on every masthead (phase 25 task 01) ------------------ #
#
# `TODO.md:3-4` — "hosts disks engines UPS disappear when in the certs/account page" and the
# operator's correction: "I did want hosts disks engines UPS badges". `Dash.initChrome()`
# builds the four badges whenever `#nav-status` exists, so the **container** is the whole
# difference between a page that has them and a page that does not — the two admin pages shipped
# without one, which is why they read as the badges vanishing rather than as two odd pages. The
# fix is the container and nothing else, so the pin is the container: on every page that renders
# the masthead, in the position the five dashboards already used (first child of
# `.masthead-right`, which is what puts it on its own row — task 02 re-justifies that row and this
# pin deliberately says nothing about which way the badges face). `tests/test_auth_api.py` keeps
# its own assertion that `/login` has none: a stranger has no fleet to be told about.

#: The container exactly as all seven signed-in pages write it (`index.html` is the reference).
NAV_STATUS_ELEMENT = '<div id="nav-status" class="gap" aria-live="polite"></div>'

#: The four badges `initChrome()` renders, in its own order.
NAV_STATUS_BADGES = ("hosts", "disks", "engines", "UPS")


def test_every_signed_in_page_carries_the_fleet_badges(client) -> None:
    """`#nav-status` is the first child of `.masthead-right` on all seven signed-in pages.

    One loop over `MARKUP_PAGES`, because the control is the same on all of them: the five
    dashboards had it, `/certs` and `/settings` grew it. The `app.js` half of the assertion is
    what makes the markup mean something — the badges are built from the container's existence,
    so a script that stopped reading `#nav-status` would turn seven `<div>`s into dead markup and
    the orphan-`id` audit alone would not say so (it also matches `#nav-status` inside the CSS).
    """
    js = _code(client.get("/static/app.js").text)
    assert "const nav = $('#nav-status');" in js, \
        "initChrome() no longer builds the badges from #nav-status, so the container is inert"
    assert "if (nav) {" in js, \
        "the container guard is gone — a page without #nav-status (only /login) would throw"
    for label in NAV_STATUS_BADGES:
        assert f"label: '{label}'" in js, f"the badge table lost {label}"
    assert "setInterval(refreshStatus, 15000)" in js, \
        "the badges' refresh cadence moved — this phase changes placement, not polling"

    for path in MARKUP_PAGES:
        header = _masthead(client.get(path).text)
        assert NAV_STATUS_ELEMENT in header, \
            f"{path} has no fleet badges in its masthead (TODO.md:3)"
        after_cluster = header[header.index('<div class="masthead-right">')
                               + len('<div class="masthead-right">'):]
        assert after_cluster.lstrip().startswith(NAV_STATUS_ELEMENT), \
            f"{path} does not render #nav-status as the first child of .masthead-right "\
            "(the five dashboards' position is what puts the badges on their own row)"
        assert header.count('id="nav-status"') == 1, f"{path} renders the badge container twice"


def test_the_nav_toggle_css_and_binding_carry_the_same_breakpoint(client) -> None:
    """Hidden by default, revealed at one breakpoint, in two files that must agree on its value.

    The base rule is *not* a literal `.nav-toggle { display: none }` and pinning that literal
    would be pinning a bug: the element also carries the shared `ghost` class, whose
    `button.ghost { display: inline-flex }` out-ranks a single-class rule and ships a visible
    button into the desktop masthead. The shipped shape is an id rule reading a token
    (`--nav-toggle-display`, `none` in `:root`), which the ≤640px block flips by re-declaring the
    token on the element — so that is what is asserted here, plus the dropdown and the four close
    paths the binding owns.
    """
    css = _code(_css(client))
    assert re.search(r"--nav-toggle-display:\s*none", css), \
        "the nav toggle is no longer hidden by default — the desktop masthead grew a ☰"
    assert re.search(r"#nav-toggle\s*\{\s*display:\s*var\(--nav-toggle-display\)", css), \
        "#nav-toggle stopped reading the token that keeps its reveal order-independent"

    nav_css = _code(_css_section(_css(client), "mobile nav"))
    media = re.search(r"@media\s*\(max-width:\s*(\d+)px\)", nav_css)
    assert media, "the mobile nav block lost its media query"
    for rule in ("--nav-toggle-display: inline-flex",   # the reveal, through task 01's token
                 "nav.tabs.is-open",                     # the links leave the row as the menu
                 "position: absolute",
                 "top: 100%",                             # pinned under the whole masthead
                 "z-index: 41",                           # one above the masthead's 40
                 "background: var(--bg-raised)",
                 "flex-wrap: wrap",                       # the controls wrap, none is hidden
                 # the safe-area inset keeps the first-row #nav-toggle out of the system
                 # top-edge zone a real phone's status bar owns (taps there never reach
                 # the page; headless emulation has no such zone, so only this pin says
                 # the bar still pads for it):
                 "padding-top: calc(.5rem + env(safe-area-inset-top, 0px))"):
        assert rule in nav_css, f"the ≤640px nav block lost `{rule}`"
    # Nothing on the phone masthead may be hidden to make the width work: the cluster wraps.
    assert ".masthead-right" in nav_css and "#nav-status" in nav_css, \
        "the mobile masthead hid the status cluster instead of wrapping it"

    js = _code(client.get("/static/app.js").text)
    binding = js[js.index("const navToggle ="):js.index("function rangeControl(")]
    assert "if (navToggle && appNav)" in binding, \
        "the binding lost the guard that makes it inert on /login"
    assert binding.count("classList.toggle('is-open'") == 1, \
        "a state change now bypasses setNavMenu(), so is-open and aria-expanded can diverge"
    for path in ("navToggle.setAttribute('aria-expanded'",
                 "navToggle.addEventListener('click'",   # close (and open) on the button
                 "event.target.closest('a')",             # close on a tab click, delegated
                 "event.key === 'Escape'",                # close on Esc…
                 "navToggle.focus()",                     # …with focus back on the opener
                 "if (!mq.matches) setNavMenu(false)"):   # close on resize back to desktop
        assert path in binding, f"the nav binding lost a close path: {path}"
    assert "mq.addEventListener" in binding, "the resize-back close was never registered"

    js_bp = re.search(r"matchMedia\('\(max-width: (\d+)px\)'\)", js)
    assert js_bp, "app.js no longer reads the nav breakpoint through matchMedia"
    assert js_bp.group(1) == media.group(1), (
        f"the nav breakpoint drifted: CSS hides the tabs below {media.group(1)}px, "
        f"app.js closes the menu below {js_bp.group(1)}px")
    assert media.group(1) == "640", "the nav breakpoint moved off the 640px the phase shipped"


# ---- the three-row masthead (phase 20 task 01) ------------------------------ #
#
# `TODO.md:5-6` asked for the per-source indicators and the `⚷ Certs ⚙ Account ☾ Dark` cluster
# each on their own line (phase 25 task 02 moved both of those lines flush right; the *rows* and
# the mechanism below are phase 20's). The markup could not change — `#nav-status` is a child
# of `.masthead-right`, and the tab structure is pinned by
# `test_the_disks_tab_is_in_the_masthead_of_every_page` — so the rows are made of line breaks:
# in a `flex-wrap: wrap` container an item whose *base* size fills the line is alone on it (the
# break happens before shrink), so `flex-basis: 100%` on `.masthead-right` starts row 2 of the
# bar and the same declaration on the dots starts row 2 *inside* it, pushing the controls to
# row 3. The alternative the task allowed — `flex-direction: column` — would have put the brand
# and the tabs on separate lines, which is why the fallback shipped. A browser proves the
# geometry at 1280 px and 360 px (`data/logs/20-task01-rows.cjs`, `masthead-rows*.png`); these
# pins keep a later re-flow from putting the buttons back on the dots' line in silence.

def _rule_body(css: str, selector: str) -> str:
    """One rule's declaration block, with the comments stripped.

    Anchored on the selector itself rather than a section slice: `.masthead-right {` must not
    satisfy a lookup for `.masthead {`, and the ≤640px block restates both selectors.
    """
    match = re.search(rf"{re.escape(selector)}\s*\{{([^}}]*)\}}", _code(css))
    assert match, f"dash.css no longer has a `{selector} {{ … }}` rule"
    return match.group(1)


def _declarations(css: str, selector: str) -> dict[str, str]:
    """That block as `{property: value}`, so a pin can ask whether a property exists at all."""
    found: dict[str, str] = {}
    for declaration in _rule_body(css, selector).split(";"):
        prop, sep, value = declaration.partition(":")
        if sep:
            found[prop.strip()] = value.strip()
    return found


def _cascade(css: str, *selectors: str) -> dict[str, str]:
    """The declarations of several rules merged in cascade order, later winning.

    Needed for the ≤640px menu: since phase 20 task 03 the dropdown's *geometry* lives on the
    closed `nav.tabs` rule and `.is-open` carries only the visible counterpart, because a box
    that does not exist cannot animate. A pin that asks "does the open menu sit at `top: 100%`
    and paint above the bar?" is asking about the element, so it has to read both rules the way
    the browser does — one duplicated `position` in two rules is the drift this avoids.
    """
    merged: dict[str, str] = {}
    for selector in selectors:
        merged.update(_declarations(css, selector))
    return merged


def test_the_masthead_is_three_rows_right_justified_at_every_width(client) -> None:
    """Brand + tabs, then the indicators, then the controls — three rows, two of them flush right.

    Every assertion here is one declaration the row layout depends on, read out of the
    **served** stylesheet: `flex-wrap` plus the two `flex-basis: 100%` rules are the rows, the
    two `justify-content` values are the right justification (phase 25 task 02, after the
    operator overruled phase 20's `flex-start`), and the absence of `margin-inline-start` on the
    cluster keeps the *mechanism* the alignment rather than the old single-row right-pinning.
    """
    css = _css(client)
    bar = _declarations(css, ".masthead")
    assert bar.get("flex-wrap") == "wrap" or bar.get("flex-direction") == "column", \
        "the masthead can no longer break into rows: indicators and controls share a line again"
    assert bar.get("flex-direction", "row") == "row", \
        "flex-direction: column puts the brand and the tabs on separate rows"
    assert "height" not in bar, \
        ".masthead has a fixed height again — three rows do not fit in --header-h and clip"
    assert bar.get("min-height") == "var(--header-h)", \
        ".masthead lost the min-height that keeps a dots-less page from collapsing to one line"
    assert bar.get("gap", "").startswith(".35rem"), \
        "the row gap the three rows need is gone from the masthead's shorthand gap"

    cluster = _declarations(css, ".masthead-right")
    assert cluster.get("flex-basis") == "100%", \
        "the control cluster no longer starts its own row under the indicators"
    assert cluster.get("justify-content") == "flex-end", \
        "the controls are no longer right-justified in their own row"
    assert "margin-inline-start" not in cluster, \
        "margin-inline-start: auto pushes the cluster back to the right edge of its own row"

    dots = _declarations(css, "#nav-status")
    assert dots.get("flex-basis") == "100%", \
        "the status indicators no longer get a row to themselves"
    assert dots.get("justify-content") == "flex-end", \
        "the indicators are no longer right-justified"


def test_the_mobile_masthead_block_declares_no_second_bar_height(client) -> None:
    """One `min-height` in the file, and the safe-area padding still on the phone bar.

    The ≤640px block used to own `height: auto` + `min-height` because the base rule was a
    fixed `--header-h`; task 01 moved the growth to the base rule, and a mobile restatement is
    exactly the pair that drifts (one says `auto`, the other a number, and the bar clips on a
    phone only). The safe-area line and the wrapping cluster are the phase-18 contract and stay.
    """
    css = _css(client)
    nav_css = _code(_css_section(css, "mobile nav"))
    block = re.search(r"\.masthead\s*\{([^}]*)\}", nav_css)
    assert block, "the ≤640px block no longer styles the masthead at all"
    for prop in ("height", "min-height", "flex-wrap"):
        assert not re.search(rf"(^|;)\s*{prop}\s*:", block.group(1)), \
            f"the ≤640px masthead re-declares `{prop}` — two rules now decide the bar's height"
    assert "row-gap: .4rem" in block.group(1), "the phone lost its tighter row gap"
    assert "padding-top: calc(.5rem + env(safe-area-inset-top, 0px))" in block.group(1), \
        "the phone bar stopped padding for the system top-edge zone the toggle sits in"
    # The dots stay one line and the cluster still wraps rather than hiding a control.
    assert "#nav-status { flex-wrap: nowrap; }" in nav_css
    assert re.search(r"\.masthead-right\s*\{[^}]*flex-wrap: wrap", nav_css)


# ---- the masthead that scrolls away (phase 20 task 02) ---------------------- #
#
# `TODO.md:10` — "The navbar is only sticky part way down certain pages on mobile? It shouldn't
# be sticky at all. We want to maximize the amount of screen space for data viewing." The quirk
# and the footprint had the same cause, so both went with the stick. What has to stay is the
# bar's second job: it is the containing block the ≤640px dropdown's `top: 100%` resolves
# against, which is why the declaration is `relative` and not the default `static`. These pins
# read the **served** stylesheet, so a re-stick or a `static` regression fails here rather than
# in a phone's hands. `data/logs/20-task02-unsticky.cjs` is the browser half: scrolled bars at
# 1280 px and 360 px, and the menu still landing under the bar.

def test_the_masthead_scrolls_away_and_stays_the_dropdown_anchor(client) -> None:
    """Not `sticky`, not `static` either: a relative bar scrolls and still anchors the menu.

    Every assertion is one half of that trade. `sticky` (with its `top: 0`) is the pinning the
    task removes and a `top` on a relative bar would shift the whole masthead down instead;
    `position: relative` is the positioned ancestor the dropdown needs; the two `z-index`es are
    the stacking sentence "the menu paints one above the bar", which survives the un-stick.
    """
    css = _css(client)
    bar = _declarations(css, ".masthead")
    assert bar.get("position") == "relative", (
        "the masthead stopped being the positioned ancestor the ≤640px dropdown resolves "
        "against — `sticky` pins the bar to the viewport, `static` moves the menu to the top "
        "of the document")
    assert "sticky" not in bar.values(), \
        ".masthead is sticky again: the bar must scroll away for data viewing (TODO.md:10)"
    assert "top" not in bar, \
        "`top` belongs to a sticky bar; on a relative one it offsets the whole masthead"
    assert bar.get("z-index") == "40", \
        ".masthead lost its z-index, so the dropdown's 41 no longer means one above the bar"

    # The mobile half of the contract: the menu still opens directly under the bar and still
    # paints above the content it overlaps — with the bar itself now free to scroll. Read as a
    # cascade: task 03 moved the box onto the closed rule so the slide has something to animate,
    # and `.is-open` is the visibility flip on top of it.
    nav_css = _code(_css_section(css, "mobile nav"))
    dropdown = _cascade(nav_css, "nav.tabs", "nav.tabs.is-open")
    assert dropdown.get("position") == "absolute" and dropdown.get("top") == "100%", \
        "the ≤640px menu no longer opens directly under the masthead"
    assert int(dropdown["z-index"]) > int(bar["z-index"]), \
        "the dropdown no longer stacks above the masthead it hangs from"


# ---- the menu that slides (phase 20 task 03) -------------------------------- #
#
# `TODO.md:11` — "I want a nice animation for the hamburger menu - a slide out and slide back in
# would be perfect. See ~/Project/Personal/brain-of-reese for an example." (The project is
# `brain_of_reese`; the pattern is its `.app-nav` closed/open transition pair plus the phase-46
# reduced-motion block.) It is pure CSS over the class flip `setNavMenu()` already performs,
# which is why `app.js` and its four close paths are untouched. What that pattern *does* force
# is a re-cut of the two rules: a `display: none` box has no intermediate state, so the closed
# menu is `visibility: hidden` now and carries the dropdown geometry the transition animates,
# while `.is-open` carries only the visible counterpart. Three questions are pinned here, in the
# order that makes the pair readable: does the closed state name the invisible, non-interactive
# start of the slide; does the open state name its visible end with the `visibility` delay
# dropped; and does `prefers-reduced-motion` name **both** states, because an open rule left out
# of that block keeps animating. `data/logs/20-task03-slide.cjs` is the browser half: the
# computed closed state, a mid-transition frame, the four close paths, the no-phantom-scroll
# check, and the snap under `prefers-reduced-motion: reduce`.

#: The one duration the slide uses, quoted into both states so a pin can demand they agree.
NAV_SLIDE_MS = "180ms ease"


def test_the_closed_phone_menu_is_the_start_of_the_slide(client) -> None:
    """Invisible, 8 px high, unhittable — and a box that exists, so it can animate.

    Every declaration is one half of the closed state the reference pattern needs. `display:
    none` is the one thing the block must **not** contain: it removes the box, and a transition
    on a box that is not rendered never runs — which is exactly why the menu used to snap, and
    why the last assertion is a regression guard and not a style preference.
    """
    nav_css = _code(_css_section(_css(client), "mobile nav"))
    closed = _declarations(nav_css, "nav.tabs")
    assert closed.get("visibility") == "hidden", \
        "the closed menu is not hidden by a property that can animate"
    assert closed.get("opacity") == "0", "the slide lost its fade: the menu opens at full ink"
    assert closed.get("transform") == "translateY(-8px)", \
        "the slide lost its 8 px rise (`TODO.md:11`): the menu appears in place"
    assert closed.get("pointer-events") == "none", \
        "an invisible menu that takes clicks steals taps from the content under it"
    assert closed.get("transition") == (
        f"opacity {NAV_SLIDE_MS}, transform {NAV_SLIDE_MS}, visibility 0s linear 180ms"), (
        "the closed state's transition is what runs on the way OUT; `visibility` must be "
        f"delayed by exactly the {NAV_SLIDE_MS} slide or the box vanishes before it fades")
    assert "display: none" not in nav_css, (
        "a `display: none` in the ≤640px nav block is a box that cannot animate — the closed "
        "menu became `visibility: hidden` in phase 20 task 03 for exactly this reason")


def test_the_open_phone_menu_is_the_visible_end_of_the_slide(client) -> None:
    """`transform: none`, and no `visibility` delay — or the menu is invisible for its own 180 ms.

    `.is-open` out-ranks `nav.tabs` (two classes to one), so these four declarations are what a
    click on `#nav-toggle` actually applies, and the transition line is restated rather than
    inherited: the open state needs the same two animated properties with the delay gone.
    """
    nav_css = _code(_css_section(_css(client), "mobile nav"))
    open_state = _declarations(nav_css, "nav.tabs.is-open")
    assert open_state.get("visibility") == "visible", "`.is-open` no longer reveals the menu"
    assert open_state.get("opacity") == "1", "the open menu is still half-faded"
    assert open_state.get("transform") == "none", \
        "the open menu never came down the 8 px, so the slide has no end"
    assert open_state.get("pointer-events") == "auto", \
        "the open menu's five links would not take a tap"
    assert open_state.get("transition") == (
        f"opacity {NAV_SLIDE_MS}, transform {NAV_SLIDE_MS}, visibility 0s"), (
        "the open state must animate the same two properties with the `visibility` delay "
        "dropped — the same duration, in the other direction")


def test_the_menu_snaps_in_both_directions_under_reduced_motion(client) -> None:
    """One reduced-motion block, and it names **both** menu states.

    The reference project's phase-46 comment is the reason: `.nav.tabs.is-open` out-specifies
    `.nav.tabs`, so stilling only the closed state leaves the open transition running and the
    menu still animates for someone who asked not to. The block is the file's only one, merged
    with the pre-existing universal rule rather than a second block that would have to be kept
    in step with it.
    """
    code = _code(_css(client))
    blocks = re.findall(r"@media\s*\(prefers-reduced-motion:\s*reduce\)", code)
    assert len(blocks) == 1, (
        f"dash.css carries {len(blocks)} reduced-motion blocks; the menu's rules belong in the "
        "one universal rule, or the two drift")
    block = re.search(r"@media\s*\(prefers-reduced-motion:\s*reduce\)\s*\{(.*?)\n\}", code, re.S)
    assert block, "the reduced-motion block no longer has a body to read"
    selector = re.search(r"(nav\.tabs[^{]*)\{", block.group(1))
    assert selector, "the reduced-motion block stopped naming the menu at all"
    named = {s.strip() for s in selector.group(1).split(",")}
    assert named == {"nav.tabs", "nav.tabs.is-open"}, (
        "the reduced-motion block must name both menu states: naming only the closed one "
        f"leaves the open transition animating — got {sorted(named)}")
    assert _declarations(block.group(1), "nav.tabs.is-open").get("transition") == "none", \
        "the named open rule stopped stilling the transition"


# ---- the masthead with no polling control (phase 21 task 01) -------------- #
#
# `TODO.md:7` — "Completely remove the pause button". The control was four things: a masthead
# button on the four dashboards, a `Space` binding, the `setPaused`/`_paused` plumbing inside
# `Dash.poll()`, and a stylesheet comment naming it as a row-3 tenant. A browser is the only
# thing that can prove the operator no longer sees a button, but the served bytes are what ship
# it, so those are what fail a test when someone puts it back.
#
# The **hidden-tab** skip is deliberately *not* part of the removal and is pinned on the same
# page for that reason: a backgrounded tab asking for nothing is idle hygiene rather than a
# decision the operator made, and a poll loop "simplified" back to an unconditional `setTimeout`
# would be invisible until a laptop battery complained.

#: Every spelling the deleted control ever had, in markup, script or stylesheet.
PAUSE_ARTIFACTS = ('id="pause"', 'name="pause"', "⏸", "▶ Paused",
                   "bindPause", "setPaused", "_paused")


def test_no_page_serves_a_button_that_stops_the_polls(client, tmp_path: Path) -> None:
    """Eight pages, eleven assets, zero pause control.

    `/login` needs its own anonymous `TestClient` for the reason every other login-page audit
    gives: this `client` is signed in, and a signed-in `GET /login` is a `303` to the dashboard,
    which would audit `/`'s bytes and call them `/login`. The other seven are read as themselves.
    """
    bodies = {path: client.get(path).text for path in MARKUP_PAGES}

    db = str(tmp_path / "no-pause-login.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2), store)
    try:
        with TestClient(app) as anon:
            response = anon.get("/login")
            assert response.status_code == 200, \
                "a signed-out /login must be the form, not a bounce"
            bodies["/login"] = response.text
    finally:
        store.close()

    assert len(bodies) == 8, "the audit lost a page; every served page owes this check"
    for path, html in bodies.items():
        for artifact in PAUSE_ARTIFACTS:
            assert artifact not in html, f"{path} serves the removed control again: {artifact!r}"

    for asset in ASSETS:
        body = client.get(asset).text
        for artifact in PAUSE_ARTIFACTS:
            assert artifact not in body, \
                f"{asset} still carries the removed control: {artifact!r}"


def test_the_poll_loop_still_idles_on_a_hidden_tab_and_binds_no_key_for_the_old_control(
    client,
) -> None:
    """What survives the deletion, pinned beside what must not come back.

    The first block is the hidden-tab behaviour the phase keeps (`document.hidden` skips the run
    and reschedules; `visibilitychange` fires one poll on return). The second is the `Space`
    binding: no `event.code` check may live in the shared script, because a key that stops the
    numbers with no control on screen to say so is the failure mode this task exists to retire.
    The third is the half of the old listener that was never about pausing — `T` still toggles
    the theme, on the same four pages it always did.
    """
    app_js = client.get("/static/app.js").text
    loop = app_js[app_js.index("function poll(fn, ms) {"):app_js.index("  // ---- chrome")]
    assert "if (stopped || inFlight || document.hidden) { schedule(); return; }" in loop, \
        "a hidden tab no longer skips its poll — the idle-hygiene guard is not the button"
    assert "document.addEventListener('visibilitychange', () => { if (!document.hidden) tick(); })" in loop, \
        "returning to a backgrounded tab no longer fires a poll — the page would sit on old numbers"

    assert "event.code" not in app_js, \
        "a key-code binding is back in the shared script — the only one it carried was the deleted control's"
    assert "'Space'" not in app_js, "the deleted control's keyboard shortcut came back"

    assert "event.key === 't' || event.key === 'T'" in app_js, \
        "`T` stopped toggling the theme: the shortcut that shared the deleted binding survives"
    for name in ("page-system.js", "page-disks.js", "page-llm.js", "page-ups.js"):
        assert "Dash.bindShortcuts();" in client.get(f"/static/{name}").text, \
            f"{name} no longer opts in to the theme shortcut it always had"


def test_the_header_status_dot_picks_up_the_disks_job(client) -> None:
    """`disks` gets its own dot instead of hiding inside `hosts`.

    The same agent can answer the 10-second utilisation poll and have a wedged SMART pass;
    one dot for both would have to be right about neither.
    """
    app_js = client.get("/static/app.js").text
    assert "{ key: 'disks', label: 'disks', href: '/disks' }" in app_js
    assert "s.dashboard === job.key" in app_js, "the dot stopped filtering by dashboard"


def test_disks_page_draws_one_card_per_physical_drive_from_the_api(client) -> None:
    """The card is a drive, keyed by the agent's device name, patched in place.

    A mount or a partition would need a filesystem field, and `/system` already answers "is
    the filesystem full"; if one leaks back in here, the page stops being about the drive.
    """
    html = client.get("/disks").text
    js = _disks_js(client)
    assert 'id="hosts"' in html and 'id="hosts-empty"' in html
    assert "fetchJSON('/api/disks/snapshot')" in js
    assert "row.path" in js and "/dev/" in js, "the card stopped naming the device it is about"
    # identity + verdict lead the card: no hero row, no big single number
    assert 'class="heroes"' not in html, "the disk card grew a hero row"
    assert "Dash.hero(" not in js
    for filesystem in ("mountpoint", "fstype", "free_bytes", "worst_mount"):
        assert filesystem not in js, f"{filesystem} leaked into the drive page"
    # built once per device and patched, so a 16-drive host does not rebuild 16 panels a poll
    assert "seen.get(row.device)" in js and "renderDiskCard(panel, row)" in js
    assert "pruneHosts(" in js, "a drive that left the host keeps its card forever"


def test_disk_cards_print_the_drive_numbers_and_colour_only_rated_ones(client) -> None:
    """Temp, power-on hours and wear, coloured by the API's verdicts and nothing else.

    The odometer is the deliberate exception: `severity.THRESHOLDS` has no `disk.power_on_hours`
    row, so the cell is written with a `null` verdict and cannot go green at 100 h or red at
    60 000 h. A drive that publishes no wear (the recorded HDD shape) prints `n/a` because
    `setTxt` is the only writer.
    """
    js = _disks_js(client)
    for field in ("smart.temp_c", "smart.power_on_hours", "smart.percentage_used",
                  "row.health"):
        assert field in js, f"{field} is no longer on the card"
    for verdict in ("severity.temp_c", "severity.percentage_used", "severity.health"):
        assert verdict in js, f"the card stopped rendering {verdict}"
    assert "severityFor" not in js, "the drive page wrote a threshold of its own"
    body = js[js.index("function renderDiskCard("):js.index("/** Text that prints nothing")]
    assert "severity.temp_c" in body and "severity.percentage_used" in body
    assert re.search(r"setMetric\(card, 'hours',[^;]*null\)", body), (
        "the odometer is being graded by something severity.py does not have")
    # the drive's own word, and `unknown` for a drive that gave none — never a green pass
    assert "'FAILED'" in body and "'unknown'" in body


def test_disk_alarm_chips_exist_only_while_a_counter_is_non_zero(client) -> None:
    """Zero and unknown both draw no chip; only a non-zero counter draws a red one.

    The `/llm` preemption rule: a permanent "0 pending sectors" row trains the eye to ignore
    it, and grading a counter green would call a quiet drive an achievement. `severity.py`
    rates none of these, so the chip's presence is the entire signal here.
    """
    js = _disks_js(client)
    for counter in ("reallocated_sector_ct", "current_pending_sector_ct",
                    "offline_uncorrectable"):
        assert counter in js, f"{counter} is no longer an alarm"
    assert "value <= 0) continue" in js, "a zero now draws a chip"
    assert "alarms.hidden = chips.length === 0" in js, "the empty chip row stays on screen"
    assert 'class="chip fail"' in js
    css = client.get("/static/dash.css").text
    assert ".alarms {" in css and ".chip.fail" in css


def test_a_host_without_smartctl_is_dimmed_with_a_one_line_why_and_never_red(client) -> None:
    """Unconfigured is not broken (invariant 3), and the three answers stay three.

    `smartctl_available` is `false` (install smartmontools — the agent said so, so the page
    may say it), `null` (nobody told us either way, so name the fix without claiming to know
    which half is missing), or the agent is not answering at all, which is a different
    sentence again. None of the three reddens anything.
    """
    js = _disks_js(client)
    html = client.get("/disks").text
    assert "smartctl not available on" in js
    assert "disk group" in js, "the why stopped naming the grant that fixes it"
    assert "smartctl_available === false" in js and "smartctl_available === true" in js
    assert "host.unreachable" in js, "a dead agent must not be reported as a missing binary"
    assert "smart_errors" in js, "the agent's own sentence is no longer printed"
    assert "classList.toggle('stale'" in js
    assert 'class="banner info why" hidden' in js, "the why-line has no home on the card"
    assert "banner fail" not in js and html.count("banner") == 0, (
        "a missing binary reddens the page")


def test_disks_charts_are_collapsed_lazy_and_cost_one_history_request_per_host(client) -> None:
    """`/system`'s chart discipline, reused: collapsed, painted only while open, one XHR.

    The request still names every series the host could draw (temperature and wear per
    drive), because `/api/disks/history` answers an unknown name as an empty series and a
    panel should never have to discover series it did not ask for.
    """
    js = _disks_js(client)
    assert '<details class="charts-box"' in js
    guard = js[js.index("function drawHostCharts("):js.index("async function renderHostCharts(")]
    assert "if (!chartsOpen(card)) return;" in guard, (
        "a collapsed stack is being built and drawn every poll")
    history = js[js.index("async function renderHostCharts("):js.index("/**\n * Drop cards")]
    assert history.count("fetchJSON(") == 1, "more than one history request for one host"
    assert "/api/disks/history" in history
    assert "streams.temp.concat(streams.wear)" in history, (
        "the request no longer names every series the panel could draw")
    prune = js[js.index("function pruneHosts("):js.index("// ---- fleet header")]
    for entry in ("state.hosts.delete", "state.disks.delete", "state.charts.delete",
                  "state.history.delete", "state.payloads.delete"):
        assert entry in prune, f"a pruned host keeps its {entry}"


def test_every_disks_chart_names_itself_for_assistive_tech(client) -> None:
    """An unlabelled plot is silence, and the legend is a sibling that labels nothing."""
    js = _code(_disks_js(client))
    labels = re.findall(r"ariaLabel: `([^`]+)`", js)
    assert len(labels) == 2, "every drive chart must name itself (temperature, wear)"
    assert all(label.startswith("${host.name}") for label in labels), (
        "a chart that does not say which host it plots belongs on no page")


def test_the_disks_fleet_header_reads_the_api_sums_and_invents_none(client) -> None:
    """The header's arithmetic is the API's (`fleet_disk_summary`), never the page's.

    Hidden below two hosts, because with one box in `HOST_TARGETS` these sums only duplicate
    that host's own cards — `/llm`'s fleet-block rule. And no cell is coloured: a count of
    drives is not a graded number (`severity.py` has no row for one).
    """
    html = client.get("/disks").text
    js = _disks_js(client)
    for element in ("fleet", "fleet-dot", "fleet-count", "fleet-disks", "fleet-smart",
                    "fleet-failed", "fleet-alarms"):
        assert f'id="{element}"' in html, f"the header lost #{element}"
    fleet = js[js.index("function renderFleet("):js.index("// ---- snapshot")]
    for path in ("fleet.hosts_live", "fleet.disks", "fleet.with_smart",
                 "fleet.health_failed", "fleet.alarm_disks"):
        assert path in fleet, f"the header no longer reads {path}"
    assert "reduce(" not in fleet and "+=" not in fleet, "the page is summing drives itself"
    assert "severity" not in fleet, "a drive count grew a verdict"
    assert "block.hidden = true" in fleet, "one host's sums duplicate its own cards"


def test_the_disk_panel_style_is_existing_vocabulary_with_no_new_palette(client) -> None:
    """`.disk` is the `.slot` shape, and the only colours it reaches for are the verdicts."""
    css = _css(client)
    block = _css_section(css, "drive panels")
    for selector in (".disks {", ".disk {", ".disk-head", ".disk-dev", ".disk-model",
                     ".disk .metrics", ".disk .alarms", ".disk .metric.warn .value",
                     ".disk .metric.fail .value"):
        assert selector in block, f"dash.css lost {selector}"
    for token in ("var(--warn)", "var(--fail)", "var(--border)", "var(--bg-sunken)",
                  "var(--text)"):
        assert token in block, f"the drive panel no longer uses {token}"
    assert "--disk" not in css, "a drive-only colour token appeared"
    assert ".stale" in css, "the dim that marks an unreadable host is gone"


def test_the_overview_prints_the_fourth_source_cadence(client) -> None:
    """`/` names every source's interval, so a drive card four minutes old reads as behaving."""
    js = client.get("/static/page-index.js").text
    assert "config.disks.interval_seconds" in js


@pytest.mark.parametrize("fixture", ["client", "data_client"])
def test_summary_carries_the_drive_block_for_programmatic_consumers(
        request, fixture: str) -> None:
    """`disks` is additive: the same configured-ness, the same hosts, no key retired.

    `client` has no targets, so it proves the block answers as `False`/`None`/`[]` instead of
    disappearing; `data_client` proves it lists the host the fleet has.
    """
    test_client = request.getfixturevalue(fixture)
    body = test_client.get("/api/summary").json()
    populated = fixture == "data_client"
    assert body["disks"]["enabled"] is populated
    assert (body["disks"]["fleet"] is not None) is populated
    assert body["disks"]["hosts"] == ([] if not populated else [
        {"name": "driveripper", "disks": None, "with_smart": None, "health_failed": None,
         "alarm_disks": None, "smartctl_available": None, "failed_devices": [],
         "unreachable": True}]), "a configured host with no payload is a row of nones"
    assert [row["name"] for row in body["disks"]["hosts"]] == [
        row["name"] for row in body["system"]["hosts"]]


def test_summary_serves_the_same_counts_the_disks_page_prints(disks_client) -> None:
    """One projection, two consumers: the summary's numbers *are* the snapshot's."""
    body = disks_client.get("/api/summary").json()
    snapshot = disks_client.get("/api/disks/snapshot").json()
    disks = body["disks"]
    assert disks["fleet"] == snapshot["fleet"], "the header would disagree with the page"
    rows = {row["name"]: row for row in disks["hosts"]}
    live = next(host for host in snapshot["hosts"] if host["name"] == "driveripper")
    assert (rows["driveripper"]["disks"], rows["driveripper"]["with_smart"],
            rows["driveripper"]["health_failed"], rows["driveripper"]["alarm_disks"]) == (
        live["summary"]["disks"], live["summary"]["with_smart"],
        live["summary"]["health_failed"], live["summary"]["alarm_disks"])
    assert rows["driveripper"]["smartctl_available"] is True
    assert rows["driveripper"]["unreachable"] is False
    assert rows["deskwork"]["unreachable"] is True
    assert rows["deskwork"]["disks"] is None, "unknown, never 0 (rule 2)"
    assert sorted(state["key"] for state in disks["states"]) == ["disks:deskwork",
                                                                 "disks:driveripper"]


def test_summary_names_the_drive_the_health_verdict_called_failed(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch, disk_snapshot: Any) -> None:
    """Which drive the hardware itself called `FAILED` is part of the fleet answer.

    A notifier reading `/api/summary` should not have to fetch a second endpoint to name the
    device, and the count and the list have to agree or one of them is wrong.
    """
    db = str(tmp_path / "summary-failed.sqlite3")
    store = SampleStore(db)
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2,
                              host_targets=(Target("driveripper", DEAD_URL),)), store)
    with TestClient(app) as test_client:
        sign_in(test_client)
        now = time.time()
        snapshot = disk_snapshot("driveripper", mode="failed")
        snapshot["ts"] = now
        result = parse_disks_snapshot("driveripper", snapshot, DisksCollector(), now=now)
        app.state.ctx.hub.jobs["disks:driveripper"].state.payload = result.payload
        row = test_client.get("/api/summary").json()["disks"]["hosts"][0]
        assert len(row["failed_devices"]) == 1
        assert row["failed_devices"][0] == result.payload["disks"][0]["device"]
        assert row["health_failed"] == result.payload["summary"]["health_failed"] == 1
    store.close()


# ---- events --------------------------------------------------------------- #

def test_events_are_returned_in_json(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    db = str(tmp_path / "events.sqlite3")
    store = SampleStore(db)
    store.log_event(Event(ts=time.time(), source="host", host="deskwork", kind="down",
                          severity="error", message="deskwork is not answering"))
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2), store)
    with TestClient(app) as client:
        sign_in(client)
        events = client.get("/api/events").json()["events"]
        assert events[0]["host"] == "deskwork"
        assert events[0]["severity"] == "error"
    store.close()


def test_event_rows_say_their_subject_once(client) -> None:
    """`poller.py` messages name their own subject, and the row prints a host chip too.

    "gufo gufo is answering again after 1 failure" reads as two problems — the same defect
    `alerts._clean_error()` already fixes for the overview's alert list. `/ups` had the
    mirror-image bug: it `replace()`d `host + ':'` *anywhere*, so "Quick battery test sent
    to apc: OK" printed as "Quick battery test sent to  OK". All three feeds now share
    `Dash.eventText()`, which strips the wrapper and a **leading** name only.
    """
    app_js = client.get("/static/app.js").text
    helper = app_js[app_js.index("function eventText("):app_js.index("// ---- DOM helpers")]
    assert "eventText" in app_js[app_js.index("return {"):], "eventText is not exported"
    assert "^UpstreamError:\\s+" in helper, "the wrapper `alerts.py` drops is back"
    assert "new RegExp" in helper and "stripped.trim() ? stripped : out" in helper, \
        "the host strip is no longer anchored to the front, or can empty a message"
    for page in ("/static/page-system.js", "/static/page-llm.js", "/static/page-ups.js"):
        js = client.get(page).text
        assert "eventText(event)" in js, f"{page} prints the raw message again"
    assert "replace(event.host" not in client.get("/static/page-ups.js").text, \
        "/ups is mangling the host name mid-message again"


# ---- the one write endpoint ------------------------------------------------ #

def test_command_endpoint_is_post_only(ups_client) -> None:
    assert ups_client.post("/api/ups/command", json={}).status_code in (400, 403, 404)
    assert ups_client.put("/api/ups/command", json={}).status_code == 405
    assert ups_client.delete("/api/ups/command").status_code == 405


def test_commands_are_offered_when_actions_are_enabled(ups_client) -> None:
    body = wait_for_payload(ups_client, "/api/ups/snapshot")
    assert body["simulated"] is True, "the simulator must label itself"
    assert body["actions_enabled"] is True
    ups = body["ups"][0]
    enabled = [item for item in ups["commands"] if item["enabled"]]
    assert enabled, "with NUT_ALLOW_ACTIONS=1 and a simulator, safe commands are sendable"
    assert all(item["risk"] in ("safe", "caution", "dangerous") for item in ups["commands"])


def test_a_safe_command_actually_reaches_the_driver(ups_client) -> None:
    body = wait_for_payload(ups_client, "/api/ups/snapshot")
    name = body["ups"][0]["name"]
    response = ups_client.post("/api/ups/command",
                              json={"ups": name, "command": "test.panel.start"})
    assert response.status_code == 200, response.text
    payload = response.json()
    assert payload["ok"] is True and payload["simulated"] is True
    events = ups_client.get("/api/events").json()["events"]
    assert any("test.panel.start" in event["message"] or "Panel test" in event["message"]
               for event in events), "every sent command must leave an audit trail"


def test_a_dangerous_command_needs_the_confirmation_word(ups_client) -> None:
    name = wait_for_payload(ups_client, "/api/ups/snapshot")["ups"][0]["name"]
    deep = "test.battery.start.deep"
    refusal = ups_client.post("/api/ups/command", json={"ups": name, "command": deep})
    assert refusal.status_code == 422
    assert "DANGER" in refusal.json()["detail"]
    assert ups_client.post("/api/ups/command",
                           json={"ups": name, "command": deep, "confirm": "DANGER"}).status_code == 200


def test_a_command_the_driver_does_not_advertise_is_refused_before_it_is_sent(
        ups_client) -> None:
    """Being in the risk catalog is not permission; `LIST CMD` from the driver is (invariant 1).

    `shutdown.return` is a real NUT command the catalog knows and this UPS does not offer,
    so the refusal must come from the advertisement check and not from the confirmation gate.
    """
    name = wait_for_payload(ups_client, "/api/ups/snapshot")["ups"][0]["name"]
    response = ups_client.post("/api/ups/command",
                               json={"ups": name, "command": "shutdown.return"})
    assert response.status_code == 400
    assert "does not advertise" in response.json()["detail"]


def test_cutting_the_output_is_refused_while_the_ups_is_already_on_battery(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """Invariant 1, the one that matters most: no power cut while the pack is carrying the load.

    Driven through the simulator's own state machine — a quick battery test puts the pack on
    battery — so the 409 comes from the same poll the buttons are drawn from, with a 0.5s
    interval to keep the wait short. Nothing here can touch real hardware: `NUT_SIMULATE=1`.
    """
    with build_client(tmp_path, monkeypatch, simulate=True, nut_host="127.0.0.1",
                      nut_allow_actions=True, nut_interval=0.5) as test_client:
        name = wait_for_payload(test_client, "/api/ups/snapshot")["ups"][0]["name"]
        start = test_client.post("/api/ups/command",
                                 json={"ups": name, "command": "test.battery.start.quick"})
        assert start.status_code == 200
        deadline = time.time() + 6.0
        card: dict[str, Any] = {}
        while time.time() < deadline:
            card = next(item for item in test_client.get("/api/ups/snapshot").json()["ups"]
                        if item["name"] == name)
            if card["on_battery"]:
                break
            time.sleep(0.05)
        assert card.get("on_battery") is True, "the quick test must put the simulated pack on battery"
        refusal = test_client.post("/api/ups/command",
                                   json={"ups": name, "command": "load.off",
                                         "confirm": "DANGER"})
        assert refusal.status_code == 409
        assert "on battery" in refusal.json()["detail"]
        # and the same command is still offered once the pack is back on line power
        assert not any(item["command"] == "load.off" and item["enabled"]
                       for item in card["commands"]), "the panel must not offer a blocked button"


class ScriptedNutClient:
    """`nut.NutClient` with the socket left out: the real code path, no battery attached.

    `AGENTS.md` keeps live tests read-only, so this is where the one write endpoint's real
    branch gets proven. The variable names are the ones `VAR_MAP` already pins from real
    upsd captures; only the replies are scripted (a fake for behaviour, per the test policy).
    """

    #: set per test: an exception instance to raise from `instcmd`, e.g. a refusal
    refusal: Exception | None = None
    sent: list[tuple[str, str]]
    logged_in: list[str]

    def __init__(self, host: str, port: int, *, timeout: float = 4.0,
                 username: str | None = None, password: str | None = None) -> None:
        self.credentials = (username, password)

    async def __aenter__(self) -> ScriptedNutClient:
        return self

    async def __aexit__(self, *_exc: object) -> None:
        return None

    async def list_ups(self) -> list[dict[str, str]]:
        return [{"name": "apc", "description": "APC Back-UPS RS 1500MS"}]

    async def list_vars(self, ups: str) -> dict[str, str]:
        return {"ups.mfr": "APC", "ups.model": "Back-UPS RS 1500MS",
                "ups.status": "OL", "battery.charge": "100", "ups.load": "18",
                "battery.voltage": "13.6", "input.voltage": "230",
                "battery.mfr.date": "2022-04", "ups.test.result": "Ok last test passed"}

    async def list_cmds(self, ups: str) -> list[str]:
        return ["test.panel.start", "beeper.mute", "load.off"]

    async def list_rw_vars(self, ups: str) -> list[str]:
        return []

    async def login(self) -> None:
        assert self.credentials[0], "a command send must authenticate as a named user"
        ScriptedNutClient.logged_in.append(str(self.credentials[0]))

    async def instcmd(self, ups: str, command: str) -> str:
        if ScriptedNutClient.refusal is not None:
            raise ScriptedNutClient.refusal
        ScriptedNutClient.sent.append((ups, command))
        return "OK Start Panel Test"


@pytest.fixture
def real_upsd_client(monkeypatch: pytest.MonkeyPatch) -> Iterator[type[ScriptedNutClient]]:
    """Swap the module-level `NutClient` so the collector and the send use the same stand-in."""
    ScriptedNutClient.sent = []
    ScriptedNutClient.logged_in = []
    ScriptedNutClient.refusal = None
    monkeypatch.setattr(nut, "NutClient", ScriptedNutClient)
    yield ScriptedNutClient


@pytest.fixture
def nut_client_app(tmp_path: Path, monkeypatch: pytest.MonkeyPatch,
                   real_upsd_client: type[ScriptedNutClient]) -> Iterator[TestClient]:
    """A non-simulated UPS app: real code paths, scripted upsd, 0.5s polls."""
    with build_client(tmp_path, monkeypatch, nut_host="127.0.0.1", nut_user="dashboards",
                      nut_password="not-the-real-one", nut_allow_actions=True,
                      nut_interval=0.5) as test_client:
        yield test_client


def test_a_real_upsd_send_authenticates_sends_and_audits(nut_client_app,
                                                         real_upsd_client) -> None:
    body = wait_for_payload(nut_client_app, "/api/ups/snapshot")
    assert body["simulated"] is False, "this test is about the branch that talks to upsd"
    name = body["ups"][0]["name"]
    response = nut_client_app.post("/api/ups/command",
                                   json={"ups": name, "command": "test.panel.start"})
    assert response.status_code == 200, response.text
    assert response.json()["simulated"] is False
    assert real_upsd_client.sent == [(name, "test.panel.start")]
    assert real_upsd_client.logged_in, "instcmd requires a LOGIN first (upsd refuses otherwise)"
    events = nut_client_app.get("/api/events").json()["events"]
    assert any(event["kind"] == "action" and name in event["message"] for event in events)


def test_a_refusal_from_upsd_is_a_502_and_an_error_event(nut_client_app,
                                                         real_upsd_client) -> None:
    real_upsd_client.refusal = nut.NutError("Access denied", code="ACCESS-DENIED")
    name = wait_for_payload(nut_client_app, "/api/ups/snapshot")["ups"][0]["name"]
    response = nut_client_app.post("/api/ups/command",
                                   json={"ups": name, "command": "beeper.mute"})
    assert response.status_code == 502
    detail = response.json()["detail"]
    assert "ACCESS-DENIED" in detail or "Access denied" in detail, detail
    assert real_upsd_client.sent == [], "a refused command was never accepted"
    events = nut_client_app.get("/api/events").json()["events"]
    failures = [event for event in events if event["kind"] == "action"
                and event["severity"] == "error"]
    assert failures, "an upsd refusal has to leave a trace, not just an HTTP status"


def test_unknown_commands_are_refused_even_with_actions_on(ups_client) -> None:
    name = wait_for_payload(ups_client, "/api/ups/snapshot")["ups"][0]["name"]
    for command in ("load.format", "rm -rf /", "INSTCMD x y"):
        response = ups_client.post("/api/ups/command", json={"ups": name, "command": command})
        assert response.status_code == 400, command


def test_commands_for_an_unknown_ups_are_404(ups_client) -> None:
    wait_for_payload(ups_client, "/api/ups/snapshot")
    response = ups_client.post("/api/ups/command",
                              json={"ups": "not-real", "command": "beeper.mute"})
    assert response.status_code == 404


def test_missing_fields_are_a_400(ups_client) -> None:
    assert ups_client.post("/api/ups/command", json={"ups": ""}).status_code == 400


def test_actions_flag_off_blocks_every_command(tmp_path: Path,
                                               monkeypatch: pytest.MonkeyPatch) -> None:
    with build_client(tmp_path, monkeypatch, simulate=True, nut_host="127.0.0.1") as client:
        body = wait_for_payload(client, "/api/ups/snapshot")
        name = body["ups"][0]["name"]
        assert body["actions_enabled"] is False
        response = client.post("/api/ups/command",
                              json={"ups": name, "command": "beeper.mute"})
        assert response.status_code == 403
        assert "NUT_ALLOW_ACTIONS" in response.json()["detail"]


def test_read_only_beats_the_actions_flag(tmp_path: Path,
                                          monkeypatch: pytest.MonkeyPatch) -> None:
    with build_client(tmp_path, monkeypatch, simulate=True, nut_host="127.0.0.1",
                      nut_allow_actions=True, read_only=True) as client:
        body = wait_for_payload(client, "/api/ups/snapshot")
        name = body["ups"][0]["name"]
        response = client.post("/api/ups/command",
                              json={"ups": name, "command": "beeper.mute"})
        assert response.status_code == 403
        commands = wait_for_payload(client, "/api/ups/commands")
        assert commands["read_only"] is True
        assert all(item["enabled"] is False for ups in commands["ups"]
                   for item in ups["commands"])


def test_ups_history_answers_for_simulated_ups(ups_client) -> None:
    wait_for_payload(ups_client, "/api/ups/snapshot")
    time.sleep(1.2)
    body = ups_client.get("/api/ups/history", params={"metrics": "ups.charge_pct",
                                                      "range": "1h"}).json()
    assert body["ups"], "the UPS page needs a name to chart before any history exists"


def response_ok(response) -> bool:
    assert response.status_code == 200, response.text
    return True


def test_samples_written_by_the_poller_are_queryable(tmp_path: Path,
                                                     monkeypatch: pytest.MonkeyPatch) -> None:
    """The write path (poller -> store) and the read path (/api/history) must agree on names."""
    db = str(tmp_path / "roundtrip.sqlite3")
    store = SampleStore(db)
    store.add_many([Sample("llm", "gufo", "llm.decode_tokens_per_second", 40.0, time.time() - 60),
                    Sample("llm", "gufo", "llm.decode_tokens_per_second", 45.0, time.time() - 30)])
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2), store)
    with TestClient(app) as client:
        sign_in(client)
        metrics = client.get("/api/metrics", params={"source": "llm"}).json()["metrics"]
        assert "llm.decode_tokens_per_second" in metrics
        points = client.get("/api/history", params={"source": "llm", "host": "gufo",
                                                   "metric": "llm.decode_tokens_per_second",
                                                   "range": "15m"}).json()["points"]
        assert [p["value"] for p in points] == [40.0, 45.0]
    store.close()


# --------------------------------------------------------------------------- #
# The certificate authority surface (phase 15 task 04)
#
# These routes mint, re-sign, and revoke the identities every agent in the fleet is dialled with,
# so the assertions are about **stored rows and wire effects** rather than about JSON being shaped
# nicely: a read that issued a certificate, a typo that wrote a row, a revocation that did not
# reach the collector, and a key that left `meta` are the four ways this surface can be wrong while
# every status code still reads 200.
#
# The fleet here is loopback ports nobody listens on. That is deliberate: nothing on this surface
# is allowed to need a live agent, so a refused connection is both the whole environment and the
# control that says "a dial was attempted, and it was not this".
# --------------------------------------------------------------------------- #

#: Three configured hosts, none of them reachable, on the scheme a protected exporter is dialled
#: by. The URL host is also what a rotated certificate's SAN must carry, so these are the SANs the
#: assertions below read.
DEAD_TARGETS = (Target(name="deskwork", url="https://127.0.0.1:1"),
                Target(name="driveripper", url="https://127.0.0.1:2"),
                Target(name="gateway", url="https://127.0.0.1:3"))

#: The whole `GET /api/certs` document and one agent row, pinned as a table so a panel that
#: retires can never shrink the payload (`/api/disks`' idiom) and task 05's page has a contract.
CERT_DOCUMENT_KEYS = {"root", "client", "agents"}
CERT_TIMESERIAL_KEYS = {"serial", "not_after"}
CERT_AGENT_KEYS = {"name", "configured", "serial", "not_after", "status", "bundle_rev",
                   "deployed_bundle_rev", "san"}


def cert_document(client: TestClient) -> dict[str, Any]:
    """`GET /api/certs`, with the status asserted: a refusal here would pass a `.get()` chain."""
    response = client.get("/api/certs")
    assert response.status_code == 200, response.text
    body = response.json()
    assert set(body) == CERT_DOCUMENT_KEYS, "the CA document grew or lost a top-level key"
    for block in ("root", "client"):
        assert set(body[block]) == CERT_TIMESERIAL_KEYS, block
        assert int(body[block]["serial"]) > 0, "a serial is the decimal text of a positive int"
        assert body[block]["not_after"] > time.time(), "a stored CA may not already be expired"
    return body


def cert_agent_rows(client: TestClient, name: str | None = None) -> list[dict[str, Any]]:
    """The agent rows, every one of them shaped, optionally just one host's."""
    rows = cert_document(client)["agents"]
    for row in rows:
        assert set(row) == CERT_AGENT_KEYS, sorted(row)
    if name is None:
        return rows
    return [row for row in rows if row["name"] == name]


def cert_context(client: TestClient) -> Any:
    """The app's `AppContext`.

    `TestClient.app` is typed as the ASGI callable it wraps, so the one cast lives here instead of
    one `# type: ignore` at every assertion that needs the store or a job.
    """
    return client.app.state.ctx  # type: ignore[attr-defined]


def cert_meta(store: SampleStore) -> dict[str, str]:
    """Every `certs.*` row, for the before/after comparisons that prove a route wrote nothing.

    Coalesced to `""` because the comparison is "did any byte of these five rows move", and an
    absent row is the empty answer to that question rather than a second kind of nothing.
    """
    return {key: store.get_meta(key) or "" for key in certs.META_KEYS}


def revoked_serials(bundle: str) -> list[str]:
    """The denylist of a bundle, as the agent reads it: the `# REVOKED <serial>` lines."""
    return [line.removeprefix(certs.REVOKED_LINE).strip()
            for line in bundle.splitlines() if line.startswith(certs.REVOKED_LINE)]


#: One PEM block out of a bundle, by text — the same read task 02's agent does with stdlib.
_PEM_BLOCK = re.compile(r"-----BEGIN [A-Z0-9 ]+-----.*?-----END [A-Z0-9 ]+-----\n", re.DOTALL)


def bundle_certs(bundle: str) -> list[x509.Certificate]:
    """The two certificates of a bundle, in the order the format writes them.

    `[0]` is the agent's own server certificate and `[1]` the root it chains to (`certs.py`'s
    `_bundle_text` order: metadata lines, agent cert, agent key, root cert). Reading them out of the
    served bytes rather than trusting the response's echo is what makes "did the rotation reach the
    artifact?" a checked claim.
    """
    blocks = [block for block in _PEM_BLOCK.findall(bundle) if "CERTIFICATE" in block]
    assert len(blocks) == 2, f"a bundle is two certificates and a key, got {len(blocks)}"
    return [x509.load_pem_x509_certificate(block.encode()) for block in blocks]


def bundle_of(client: TestClient, name: str) -> str:
    """The served bundle, asserted to still be a bundle (2 certs, 1 key) before it is compared."""
    response = client.get(f"/api/certs/{name}/bundle")
    assert response.status_code == 200, response.text
    assert response.headers["content-type"].startswith("application/x-pem-file")
    assert "no-store" in response.headers["cache-control"], "a private key may not be cached"
    blocks = re.findall(r"-----BEGIN [A-Z0-9 ]+-----", response.text)
    assert blocks.count("-----BEGIN CERTIFICATE-----") == 2, blocks
    assert blocks.count("-----BEGIN PRIVATE KEY-----") == 1, blocks
    return response.text


def stored_bundle(store: SampleStore, name: str) -> str:
    """The bundle exactly as the `certs.agents` row holds it."""
    row: dict[str, Any] = json.loads(store.get_meta(certs.META_AGENTS) or "{}")
    return str(row[name]["bundle"])


def cert_events(client: TestClient) -> list[dict[str, Any]]:
    return client.get("/api/events", params={"source": "certs"}).json()["events"]


def cert_hosts(count: int) -> tuple[Target, ...]:
    return DEAD_TARGETS[:count]


@pytest.mark.parametrize("hosts", [0, 1, 3], ids=["none", "one", "three"])
def test_the_cert_list_is_the_stored_table_for_zero_one_and_three_hosts(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch, hosts: int) -> None:
    """The list works with no fleet at all, and says *unissued* rather than omitting a host.

    The CA exists whether or not `HOST_TARGETS` does — a fresh database boots with a root and a
    client certificate — so this is not the `/api/disks` "not configured" surface and does not 404.
    A configured host with nothing issued still gets a row (invariant 3: a machine that is deployed
    and not yet installed is not an absent machine), with `None` and not `0` where there is no
    certificate (rule 2).
    """
    with build_client(tmp_path, monkeypatch, host_targets=cert_hosts(hosts),
                      host_interval=3600.0) as client:
        rows = cert_agent_rows(client)
        assert len(rows) == hosts, "one row per configured host, and no more"
        assert [row["name"] for row in rows] == sorted(row["name"] for row in rows), (
            "one order in the payload and one in the table")
        for row in rows:
            assert row["configured"] is True
            assert row["status"] == "unissued", "nothing has been signed for it yet"
            assert row["serial"] is None and row["bundle_rev"] is None, "no invented zeros"
            assert row["deployed_bundle_rev"] is None, "nobody has answered, so nobody reported"
            assert row["san"] == [], "no names on record, not a certificate with no names"


def test_the_cert_list_carries_the_rev_the_agent_reported(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """`deployed_bundle_rev` is what the host said about itself, not what the CA hopes.

    Task 05's "stale bundle" sentence is a comparison of two numbers that come from two different
    places: the row this dashboard issued and the `agent` block of the last `system` payload. Both
    halves are pinned here, including the direction that matters — issued 2 against deployed 1 is
    the operator's "install the new bundle" case, and it has to be visible rather than smoothed
    over.
    """
    with build_client(tmp_path, monkeypatch, host_targets=cert_hosts(1),
                      host_interval=3600.0) as client:
        assert client.post("/api/certs/deskwork/rotate").status_code == 200
        job = cert_context(client).hub.jobs["host:deskwork"]
        assert cert_agent_rows(client, "deskwork")[0]["deployed_bundle_rev"] is None, (
            "a host that has never answered reports nothing")
        job.state.payload = {"name": "deskwork", "agent": {"tls": True, "bundle_rev": 1}}
        assert cert_agent_rows(client, "deskwork")[0]["deployed_bundle_rev"] == 1
        assert client.post("/api/certs/deskwork/rotate").json()["bundle_rev"] == 2
        row = cert_agent_rows(client, "deskwork")[0]
        assert (row["bundle_rev"], row["deployed_bundle_rev"]) == (2, 1), "the stale pair, both"
        # A token-mode agent publishes no `agent.tls` block at all, and that is `n/a`, not rev 0.
        job.state.payload = {"name": "deskwork", "agent": {"version": "1.0.0"}}
        assert cert_agent_rows(client, "deskwork")[0]["deployed_bundle_rev"] is None


def test_an_entry_for_a_host_that_left_the_config_is_listed_and_not_writable(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """A row issued for a machine that has gone is a key still sitting in the table.

    Listing it is the honest answer (`/certs` is where you learn you still hold one); refusing to
    rotate or revoke it is the same invariant from the other side — `HOST_TARGETS` is what this
    dashboard dials, and a name it no longer dials is not a name to install a bundle on. The row is
    written straight to the store because that is the only way this state arises: a host removed
    from the config, never a route that created it.
    """
    with build_client(tmp_path, monkeypatch, host_targets=cert_hosts(1),
                      host_interval=3600.0) as client:
        store: SampleStore = cert_context(client).store
        certs.issue_agent_cert(store, certs.read_state(store), "old-host", ["10.9.8.7"])

        rows = cert_agent_rows(client)
        assert [row["name"] for row in rows] == ["deskwork", "old-host"]
        ghost = rows[1]
        assert ghost["configured"] is False, "listed, but this dashboard does not dial it"
        assert ghost["status"] == certs.ACTIVE and ghost["bundle_rev"] == 1
        assert ghost["deployed_bundle_rev"] is None, "no job means no report, not rev 0"
        assert client.post("/api/certs/old-host/rotate").status_code == 404
        assert client.post("/api/certs/old-host/revoke").status_code == 404
        assert cert_events(client) == [], "a refusal is not an audit line"


def test_a_cert_route_for_an_unknown_name_dials_nothing_and_writes_nothing(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """The invariant-3 gate on the per-host routes, taken before anything can have a side effect.

    `not-installed` is refused in the first line of each route, so no client is built, no store row
    is written, and no key is minted. All three are measured: the two network spies raise, `set_meta`
    is watched for any `certs.*` write, and the five rows are compared byte for byte. A typo that
    minted a certificate would be invisible on every status code and permanent in the table.
    """
    with build_client(tmp_path, monkeypatch, host_targets=cert_hosts(1),
                      host_interval=3600.0) as client:
        store: SampleStore = cert_context(client).store
        calls: list[str] = []
        written: list[str] = []

        async def spy_get(self: Any, url: Any, **kwargs: Any) -> Any:
            calls.append(f"GET {url}")
            raise AssertionError(f"an unconfigured cert name dialled {url}")

        def spy_fetch(*args: Any, **kwargs: Any) -> Any:
            calls.append("fetch_snapshot")
            raise AssertionError("an unconfigured cert name fetched an agent snapshot")

        real_set_meta = SampleStore.set_meta

        def spy_set_meta(self: SampleStore, key: str, value: str) -> None:
            written.append(key)
            real_set_meta(self, key, value)

        monkeypatch.setattr(httpx.AsyncClient, "get", spy_get)
        monkeypatch.setattr("dashboards.collectors.fetch_snapshot", spy_fetch)
        monkeypatch.setattr(SampleStore, "set_meta", spy_set_meta)
        before = cert_meta(store)

        for response in (client.get("/api/certs/not-configured/bundle"),
                         client.post("/api/certs/not-configured/rotate"),
                         client.post("/api/certs/not-configured/revoke")):
            assert response.status_code == 404, response.text
            body = response.json()
            assert body["configured"] is False
            assert "HOST_TARGETS" in body["detail"], "the sentence names the fix"

        assert calls == [], "the gate is in front of the network, not behind it"
        assert [key for key in written if key.startswith("certs.")] == [], "a write happened"
        assert cert_meta(store) == before, "the stored CA and agent table did not move"
        assert cert_events(client) == [], "and no audit line was written for a name that is not here"
        # …and the same route still works for the host that *is* configured, so the refusal above
        # is the gate and not a broken router.
        assert client.post("/api/certs/deskwork/rotate").status_code == 200


def test_rotating_a_host_mints_the_bundle_it_asks_for(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """Rotate is also *issue*: first call is `bundle_rev` 1, and the SAN is the config's address.

    The SAN assertion is the one a rollout fails on silently — a certificate that does not name the
    address the dashboard dials is a handshake error and a red source, not a warning — so it is read
    out of the served bundle's own certificate rather than out of the response's echo.
    """
    with build_client(tmp_path, monkeypatch, host_targets=cert_hosts(1),
                      host_interval=3600.0) as client:
        store: SampleStore = cert_context(client).store
        body = client.post("/api/certs/deskwork/rotate").json()
        assert body["ok"] is True and body["status"] == certs.ACTIVE
        assert body["bundle_rev"] == 1 and body["serial"] and body["not_after"] > time.time()
        assert body["san"] == ["127.0.0.1", "deskwork"], "the dialled address and the name"

        cert = bundle_certs(bundle_of(client, "deskwork"))[0]
        names = cert.extensions.get_extension_for_class(
            x509.SubjectAlternativeName).value.get_values_for_type(x509.IPAddress)
        assert names == [ipaddress.ip_address("127.0.0.1")], "an IP SAN, or an IP dial fails"
        assert cert.subject == x509.Name([x509.NameAttribute(NameOID.COMMON_NAME, "deskwork")])

        events = cert_events(client)
        assert len(events) == 1 and events[0]["kind"] == "cert-rotated"
        assert events[0]["host"] == "deskwork" and events[0]["message"] == (
            "agent certificate rotated for deskwork")
        assert events[0]["data"] == {"bundle_rev": 1}

        second = client.post("/api/certs/deskwork/rotate").json()
        assert second["bundle_rev"] == 2 and second["serial"] != body["serial"]
        # The new identity is not on the denylist: rotation replaces an identity, it does not strike
        # one out, and a bundle that listed its own serial would refuse the client it ships.
        bundle = bundle_of(client, "deskwork")
        assert revoked_serials(bundle) == [], revoked_serials(bundle)
        assert second["serial"] not in bundle.splitlines(), "no denylist line for the live serial"
        assert stored_bundle(store, "deskwork") == bundle, "served bytes are the stored bytes"


def test_revoking_a_host_marks_the_table_and_the_next_poll_refuses_without_a_dial(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """The API half of the revocation chain: this route is what task 03's refusal reads.

    The control is the sentence from *before* the click (`unreachable`, which is what a dial to a
    dead port says), and after it the poll has to say `agent certificate revoked` with a spy on
    `httpx.AsyncClient.get` proving no socket was opened. The stored denylist is the other half: an
    agent holding a bundle that omits the serial keeps accepting the client it was given.
    """
    with build_client(tmp_path, monkeypatch, host_targets=cert_hosts(1),
                      host_interval=0.05, disks_interval=0.05) as client:
        store: SampleStore = cert_context(client).store
        wait_for_source_error(client, "host:deskwork", "unreachable")
        serial = client.post("/api/certs/deskwork/rotate").json()["serial"]

        body = client.post("/api/certs/deskwork/revoke").json()
        assert body["ok"] is True and body["status"] == certs.REVOKED
        assert body["serial"] == serial, "revocation marks the identity it has, it does not replace"
        assert body["hint"] and "next poll" in body["hint"]

        calls: list[str] = []

        async def spy_get(self: Any, url: Any, **kwargs: Any) -> Any:
            calls.append(str(url))
            raise AssertionError(f"a revoked agent was dialled at {url}")

        monkeypatch.setattr(httpx.AsyncClient, "get", spy_get)
        for key in ("host:deskwork", "disks:deskwork"):
            error = wait_for_source_error(client, key, "agent certificate revoked")
            assert "unreachable" not in error
        assert calls == []

        assert revoked_serials(bundle_of(client, "deskwork")) == [serial]
        events = cert_events(client)
        assert [row["kind"] for row in events] == ["cert-revoked", "cert-rotated"]
        assert events[0]["message"] == "agent certificate revoked for deskwork"
        assert certs.agent_status(store, "deskwork") == certs.REVOKED, (
            "the collector's own read agrees with the row the route wrote")


def test_root_rotation_reissues_every_host_and_answers_restart_required(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """One action re-arms the fleet — and says the part it cannot do from inside the process.

    `restart_required` is not decoration: the CA and the client pair are startup material, so the
    table is new immediately while the sockets keep the old identity. The page (task 05) prints
    that sentence because the API answered it, and the alternative is an operator who rotated a
    root and watches a fleet that still chains to the previous one.
    """
    with build_client(tmp_path, monkeypatch, host_targets=cert_hosts(3),
                      host_interval=3600.0) as client:
        store: SampleStore = cert_context(client).store
        for target in DEAD_TARGETS:
            assert client.post(f"/api/certs/{target.name}/rotate").status_code == 200
        before = cert_document(client)
        rows_before = {row["name"]: row for row in before["agents"]}
        root_pem_before = store.get_meta(certs.META_ROOT_CERT) or ""
        key_before = store.get_meta(certs.META_ROOT_KEY) or ""
        assert root_pem_before and key_before, "both halves of the CA exist before the rotation"

        body = client.post("/api/certs/root/rotate").json()
        assert body["ok"] is True and body["restart_required"] is True
        assert body["agents"] == 3
        assert body["root"]["serial"] != before["root"]["serial"], "a fresh root"

        after = cert_document(client)
        assert after["root"] == body["root"], "the list reports what the rotation wrote"
        assert after["client"]["serial"] != before["client"]["serial"], "and a fresh client leaf"
        for row in after["agents"]:
            was = rows_before[row["name"]]
            assert row["bundle_rev"] == was["bundle_rev"] + 1, "every host reissued, rev bumped"
            assert row["serial"] != was["serial"] and row["status"] == certs.ACTIVE
            bundle = bundle_of(client, row["name"])
            leaf, root = bundle_certs(bundle)
            assert leaf.serial_number == int(row["serial"]), "the served bundle is the listed one"
            assert root.serial_number == int(after["root"]["serial"]), (
                "and it chains to the authority the list now reports")
            assert revoked_serials(bundle) == [], "the denylist resets with the generation"
        assert store.get_meta(certs.META_ROOT_KEY) != key_before
        assert store.get_meta(certs.META_ROOT_CERT) != root_pem_before
        assert root_pem_before not in "".join(cert_meta(store).values()), (
            "the old root is gone")
        events = cert_events(client)
        assert events[0]["kind"] == "cert-root-rotated"
        assert events[0]["message"] == (
            "root certificate rotated — every agent certificate reissued, restart required")
        assert events[0]["data"] == {"agents": 3}


def test_the_bundle_route_names_a_file_and_changes_when_the_identity_does(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """Byte-identical to the stored row, an `attachment`, and different bytes after a reissue.

    This is the installer's input (task 06), so the claim is about bytes and not about a bundle
    that merely re-verifies: `install-agent.sh` is handed the file and compares nothing else.
    """
    with build_client(tmp_path, monkeypatch, host_targets=cert_hosts(1),
                      host_interval=3600.0) as client:
        store: SampleStore = cert_context(client).store
        missing = client.get("/api/certs/deskwork/bundle")
        assert missing.status_code == 404, "nothing issued yet, so nothing to download"
        body = missing.json()
        assert body["configured"] is True and body["issued"] is False, "not the same 404"
        assert "rotate" in body["detail"], "and the answer names the way to get one"

        first = client.post("/api/certs/deskwork/rotate").json()["serial"]
        response = client.get("/api/certs/deskwork/bundle")
        assert response.headers["content-disposition"] == (
            'attachment; filename="agent-deskwork.bundle"')
        assert response.text == stored_bundle(store, "deskwork")

        client.post("/api/certs/deskwork/rotate")
        second = client.post("/api/certs/deskwork/rotate").json()["serial"]
        assert second != first
        updated = client.get("/api/certs/deskwork/bundle")
        assert updated.text != response.text, "a reissue changes the served bytes"
        assert updated.text == stored_bundle(store, "deskwork")


def test_no_certificate_material_leaves_meta_through_the_cert_surface(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """invariant 6 on the API that owns the keys: serials and dates go out, PEMs do not.

    Every write here is exercised first, so the grep is over a table that has been rotated and
    revoked rather than a pristine one, and it covers both the payloads a browser reads and the
    stored event rows those payloads are built from — an event row is kept forever, which is what
    makes a PEM in a message permanent rather than transient.
    """
    with build_client(tmp_path, monkeypatch, host_targets=cert_hosts(2),
                      host_interval=3600.0) as client:
        store: SampleStore = cert_context(client).store
        client.post("/api/certs/deskwork/rotate")
        client.post("/api/certs/driveripper/rotate")
        client.post("/api/certs/driveripper/revoke")
        client.post("/api/certs/root/rotate")
        secrets = [value for value in cert_meta(store).values() if value]
        assert any("PRIVATE KEY" in value for value in secrets), "the table really does hold keys"

        for path in ("/api/certs", "/api/health", "/api/events", "/api/summary", "/api/config"):
            text = client.get(path).text
            for marker in ("BEGIN CERTIFICATE", "PRIVATE KEY", "BUNDLE-REV"):
                assert marker not in text, f"{path} served {marker}"
        assert client.get("/api/health").json()["db"], "health still answers, keys or no keys"
        for event in store.recent_events(50, source="certs"):
            assert "BEGIN" not in event.message and "PRIVATE KEY" not in event.message
            assert not any(secret in json.dumps(event.as_json()) for secret in secrets)


def test_a_host_named_root_cannot_be_rotated_past_the_certificate_authority(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """`/api/certs/root/rotate` and `/api/certs/{name}/rotate` are one URL for a host called root.

    The CA route is registered first, so it wins — which means the wrong button would rotate the
    whole authority instead of one host's leaf. Refusing with the reason is the only honest answer:
    the alternative is a fleet-wide outage behind a click that looked like routine maintenance.
    """
    with build_client(tmp_path, monkeypatch,
                      host_targets=(Target(name="root", url="https://127.0.0.1:1"),),
                      host_interval=3600.0) as client:
        store: SampleStore = cert_context(client).store
        before = cert_document(client)["root"]["serial"]
        refused = client.post("/api/certs/root/rotate")
        assert refused.status_code == 409, refused.text
        assert "rename" in refused.json()["detail"], "the sentence says what to do"
        assert cert_document(client)["root"]["serial"] == before, "and the CA did not move"
        assert cert_events(client) == []
        assert cert_meta(store)[certs.META_AGENTS] == "{}", "nothing was issued for the name either"


def test_a_read_of_the_cert_surface_issues_nothing_and_writes_nothing(
        tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
    """A GET that mints a certificate is the surprise this route must never be.

    `certs.ensure_certs` is the bootstrapping read and `certs.read_state` is the request-time one;
    making `ensure_certs` explode is what proves the difference rather than asserting it in prose,
    and the meta rows are compared byte for byte across three reads.
    """
    with build_client(tmp_path, monkeypatch, host_targets=cert_hosts(1),
                      host_interval=3600.0) as client:
        store: SampleStore = cert_context(client).store
        before = cert_meta(store)

        def explode(*args: Any, **kwargs: Any) -> Any:
            raise AssertionError("a GET tried to bootstrap the certificate authority")

        monkeypatch.setattr(certs, "ensure_certs", explode)
        assert cert_agent_rows(client)
        assert cert_document(client)["root"]["serial"] == str(
            x509.load_pem_x509_certificate(
                str(before[certs.META_ROOT_CERT]).encode()).serial_number)
        # A bundle that has not been issued is still a 404 rather than a mint, on a read too.
        assert client.get("/api/certs/deskwork/bundle").status_code == 404
        assert cert_meta(store) == before, "three reads, no write"
        assert cert_events(client) == []


# --------------------------------------------------------------------------- #
# phase 14 task 04: the endpoint budgets
#
# `store_perf.BUDGETS` is the one table of ceilings (it is what the probe's report and the notes
# render, so a ceiling relaxed in one place is relaxed everywhere). The ceilings are 2-3x the
# measured "after" on the seeded production-shaped store, which makes them a regression gate
# rather than a stopwatch: the `/system` page's own chart request costs ~2 ms and still gets
# 100 ms, while putting a full-table scan back on a per-request path crosses by three orders of
# magnitude. Wall time lives behind `--store-perf` for that reason; what runs in every `uv run
# pytest` is the key-name pin below, because a budget that silently stops being priced is as
# useless as a budget that is crossed.
# --------------------------------------------------------------------------- #


def test_every_http_budget_names_a_route_the_probe_prices(tmp_path: Path) -> None:
    """The stale-pointer check for the HTTP half, on a throwaway store.

    `measure_http` is what the priced test runs, and it owns the request shapes; if a key there is
    renamed, or a route stops being measured, the priced test would report the gap rather than the
    cost — which is why this asserts the key set here, cheaply, on every run.
    """
    report = store_perf.measure_budget_http(tmp_path / "budget-keys.sqlite3",
                                            hosts=("driveripper",), metrics=("cpu.usage_pct",))
    assert set(report["http"]) == set(store_perf.HTTP_MEASURED_KEYS), (
        "the HTTP pass and the budget table no longer describe the same requests")
    assert store_perf.missing_budget_keys(report, ("http",)) == []
    # and the request the budgets describe is the one the task names: 3 hosts x 9 series
    nine = store_perf.HISTORY_METRICS
    assert len(nine) == 9, "the 90 d budget is priced against a 3x9 request, not some other shape"


def test_metrics_stops_scanning_for_series_names_once_the_hub_is_polling(
    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
) -> None:
    """The live shape behind one budgeted endpoint, guarded by statements rather than a clock.

    Task 04's watch caught `/api/metrics` answering with its full `SELECT DISTINCT` scan on
    practically every call of the running server (535 ms, measured): task 02's cache was invalidated
    by every sample write, and the hub writes every 2-300 s, so the cache never lived long enough to
    serve. The store-level half of this lives in `tests/test_store.py`; this is the half that says
    the *endpoint* is what stops scanning, on the app the operator runs.
    """
    db = str(tmp_path / "metrics-busy.sqlite3")
    store = SampleStore(db)
    store.add_many([Sample("host", "driveripper", "cpu.usage_pct", 1.0, time.time()),
                    Sample("host", "deskwork", "cpu.usage_pct", 1.0, time.time())])
    app = create_app(Settings(db_path=db, admin_password=ADMIN_PASSWORD,
                              pbkdf2_iterations=FAST_PBKDF2), store)
    try:
        with TestClient(app) as http:
            sign_in(http)
            assert "cpu.usage_pct" in http.get("/api/metrics", params={"source": "host"}).json()["metrics"]

            # a poll of series the store already has, then the same request with the log open
            store.add_many([Sample("host", "driveripper", "cpu.usage_pct", 2.0, time.time()),
                            Sample("host", "deskwork", "cpu.usage_pct", 2.0, time.time())])
            seen: list[str] = []
            # the statement log is the test: `SampleStore._db` is the handle the request runs on
            store._db.set_trace_callback(seen.append)
            try:
                assert "cpu.usage_pct" in http.get("/api/metrics",
                                                   params={"source": "host"}).json()["metrics"]
            finally:
                store._db.set_trace_callback(None)
            assert [s for s in seen if "DISTINCT metric" in s] == [], (
                f"`/api/metrics` went back to the table while nothing changed: {seen}")

            # and a source that starts publishing something new is in the very next answer
            store.add("host", "driveripper", "gpu.busy_pct@0", 1.0)
            assert "gpu.busy_pct@0" in http.get("/api/metrics",
                                                params={"source": "host"}).json()["metrics"]
    finally:
        store.close()


@pytest.mark.store_perf
def test_the_budgeted_http_paths_fit_their_pinned_margins(perf_store_path: Path) -> None:
    """`/api/health`, `/api/metrics`, `/api/system/history` (1 h and 90 d), `/api/summary`.

    Priced through the real ASGI gate with a signed-in session, on the seeded 6.4 M-row store —
    the same call the operator's browser makes, in-process so no network is measured. This is the
    line `TODO.md:7` is about: `/api/health` used to answer in 1.27 s because it counted the whole
    `sample` table on every poll, on every tab.
    """
    report = store_perf.measure_budget_http(perf_store_path)
    print()
    print(store_perf.render_budgets_markdown(store_perf.budget_rows(report, ("http",))))
    assert store_perf.budget_violations(report, ("http",)) == []