feat(chat): invalidate saved chats on sources sync — versioned stamps, stale marker, Regenerate against the new index

tests/unit/test_sources_meta.py

@@ -0,0 +1,101 @@
+"""Unit: sources-version counter helpers (phase 53, task 01).
+
+``app.rag.sources_meta`` runs against the local compose Postgres
+(``podman compose up -d db``) — the house DB-test pattern: the helpers
+are thin session wrappers whose contract (seeded single row, flush-not
+commit, defensive absence) only holds against a real database. Skips
+with clear instructions when the stack is not up.
+
+A fixture resets ``sources_meta`` to the migration-0010 seed state
+(id 1, version 0) before and after every test, so the suite leaves the
+dev DB exactly as the migration left it.
+"""
+from __future__ import annotations
+
+import pytest
+from sqlalchemy import text
+from sqlalchemy.orm import Session
+
+from app.db import SessionLocal
+from app.models import SourcesMeta
+from app.rag.sources_meta import bump_sources_version, current_sources_version
+
+
+@pytest.fixture()
+def seeded_sources_meta(db: Session):
+    """Reset the counter to the migration-0010 seed (id 1, version 0)."""
+    db.execute(text("DELETE FROM sources_meta"))
+    db.add(SourcesMeta(id=1, version=0))
+    db.commit()
+    yield
+    db.execute(text("DELETE FROM sources_meta"))
+    db.add(SourcesMeta(id=1, version=0))
+    db.commit()
+
+
+def test_current_absent_row_returns_zero_without_raising(
+    db: Session, seeded_sources_meta: None
+) -> None:
+    """Defensive: a deleted seed row reads as 0 — never an exception."""
+    db.execute(text("DELETE FROM sources_meta"))
+    db.commit()
+    assert current_sources_version(db) == 0
+
+
+def test_first_bump_zero_to_one(db: Session, seeded_sources_meta: None) -> None:
+    """Seeded at 0 (the pre-counter KB), the first bump returns 1 and
+    ``current`` reflects it."""
+    assert current_sources_version(db) == 0
+    assert bump_sources_version(db) == 1
+    db.commit()  # the caller commits — the helper only flushes
+    assert current_sources_version(db) == 1
+
+
+def test_second_bump_increments(db: Session, seeded_sources_meta: None) -> None:
+    """Bumps are monotonic: 0 → 1 → 2, one step per KB-changing sync."""
+    assert bump_sources_version(db) == 1
+    db.commit()
+    assert bump_sources_version(db) == 2
+    db.commit()
+    assert current_sources_version(db) == 2
+
+
+def test_bump_absent_row_upserts_to_one(db: Session, seeded_sources_meta: None) -> None:
+    """Upsert semantics: a deleted seed row is recreated by the first
+    bump (version 0 → 1), never left dangling."""
+    db.execute(text("DELETE FROM sources_meta"))
+    db.commit()
+    assert bump_sources_version(db) == 1
+    db.commit()
+    row = db.get(SourcesMeta, 1)
+    assert row is not None, "the single row must be recreated"
+    assert row.id == 1
+    assert row.version == 1
+    assert row.updated_at is not None, "updated_at must be server-stamped"
+
+
+def test_bump_flushes_without_committing(db: Session, seeded_sources_meta: None) -> None:
+    """The helper flushes, it does not commit: a rolled-back session
+    must roll the bump back with it (each sync path owns its
+    transaction)."""
+    assert bump_sources_version(db) == 1
+    db.rollback()
+    assert current_sources_version(db) == 0, "the uncommitted bump must roll back"
+
+
+def test_bumps_in_separate_sessions_progress(db: Session, seeded_sources_meta: None) -> None:
+    """One writer at a time is the deployment reality, but two bumps in
+    two sessions must not race to the same value: the second session
+    sees the committed increment and lands on the next generation."""
+    assert bump_sources_version(db) == 1
+    db.commit()
+
+    other = SessionLocal()
+    try:
+        assert bump_sources_version(other) == 2
+        other.commit()
+    finally:
+        other.close()
+
+    db.expire_all()  # drop the stale identity-map state
+    assert current_sources_version(db) == 2