feat(import): user-extensible BOR_IMPORT_EXTENSIONS — any well-formed extension, A9 family stays the default

tests/unit/test_config.py

@@ -8,7 +8,7 @@ import pytest
 from pydantic import ValidationError
 from pydantic_settings import SettingsError
 
-from app.config import _ALLOWED_IMPORT_EXTENSIONS, Settings  # pyright: ignore[reportPrivateUsage]
+from app.config import _DEFAULT_IMPORT_EXTENSIONS, Settings  # pyright: ignore[reportPrivateUsage]
 
 
 def _settings(**kwargs: Any) -> Settings:
@@ -57,15 +57,15 @@ NEW_A9_FORMATS = (
 )
 
 
-def test_allowed_import_extensions_contains_all_seventeen_formats() -> None:
-    """The validator's base set is the full A9 set: the original seven
-    plus the ten added 2026-08-27 (quadlet family + ``j2``). The
-    never-widen contract bounds :py:data:`import_extensions` against
-    exactly this set."""
+def test_default_import_extensions_is_the_full_a9_family() -> None:
+    """Phase 56: the built-in default is the full A9 set — the original
+    seven plus the ten added 2026-08-27 (quadlet family + ``j2``). It is
+    the default and the ``.env.example`` example, NOT a ceiling: the
+    validator accepts any well-formed extension beyond it."""
     assert {
         "md", "markdown", "txt", "yaml", "yml", "json", "py",
         *NEW_A9_FORMATS,
-    } == _ALLOWED_IMPORT_EXTENSIONS
+    } == _DEFAULT_IMPORT_EXTENSIONS
 
 
 def test_default_import_extensions_include_the_ten_new_formats() -> None:
@@ -151,34 +151,51 @@ def test_import_extensions_env_override_is_a_csv_list(monkeypatch) -> None:
     assert s.import_extension_set == {".md", ".yml"}
 
 
-def test_import_extensions_rejects_unknown_format(monkeypatch) -> None:
-    """A typo in the CSV fails at startup (loudly), not by silently
-    walking zero files."""
-    monkeypatch.setenv("BOR_IMPORT_EXTENSIONS", "md,docx")
-    with pytest.raises(ValidationError, match="docx"):
-        _settings()
+def test_import_extensions_accepts_novel_extension(monkeypatch) -> None:
+    """Phase 56 (owner permission 2026-08-31): the A9 family is the
+    default, not the ceiling — a novel well-formed extension (``sh``) is
+    accepted and simply becomes importable."""
+    monkeypatch.setenv("BOR_IMPORT_EXTENSIONS", "md,sh")
+    s = _settings()
+    assert s.import_extension_set == {".md", ".sh"}
 
 
-def test_import_extensions_rejects_empty(monkeypatch) -> None:
-    monkeypatch.setenv("BOR_IMPORT_EXTENSIONS", "   ")
-    with pytest.raises(ValidationError):
-        _settings()
+def test_import_extensions_normalizes_case_and_leading_dot(monkeypatch) -> None:
+    """Case and a leading dot are both tolerated (unchanged tolerance)."""
+    monkeypatch.setenv("BOR_IMPORT_EXTENSIONS", "MD,.Py")
+    s = _settings()
+    assert s.import_extension_set == {".md", ".py"}
+
+
+def test_import_extensions_rejects_empty(monkeypatch: pytest.MonkeyPatch) -> None:
+    """A blank list would silently import nothing — fail loudly at
+    startup, naming the field (empty, whitespace-only, and comma-only
+    all parse to zero formats)."""
+    for value in ("", "   ", ",,"):
+        monkeypatch.setenv("BOR_IMPORT_EXTENSIONS", value)
+        with pytest.raises(ValidationError, match="import_extensions"):
+            _settings()
 
 
 def test_import_extensions_validator_accepts_new_a9_formats(monkeypatch) -> None:
-    """A9 revised 2026-08-27: the new names are first-class — the
-    never-widen contract now holds against the widened base set, so a
-    narrowing CSV with quadlet/jinja names is accepted."""
+    """A9 revised 2026-08-27: quadlet/jinja names are first-class default
+    formats — a CSV using them (a narrowing of the default family) is
+    accepted."""
     monkeypatch.setenv("BOR_IMPORT_EXTENSIONS", "md,container,j2")
     s = _settings()
     assert s.import_extension_set == {".md", ".container", ".j2"}
 
 
-def test_import_extensions_validator_still_rejects_unknown(monkeypatch) -> None:
-    """Truly unknown extensions still fail loudly at startup (the
-    validator is intact — only the allowed base set widened)."""
-    monkeypatch.setenv("BOR_IMPORT_EXTENSIONS", "md,xyz")
-    with pytest.raises(ValidationError, match="xyz"):
+def test_import_extensions_rejects_malformed_tokens(monkeypatch: pytest.MonkeyPatch) -> None:
+    """The shape guard (``^[a-z0-9]{1,16}$``) is the typo guard — it
+    keeps punctuation and path-ish values out of the set, naming the
+    offending token(s), while any extension a file could actually be
+    suffixed with still goes through."""
+    monkeypatch.setenv("BOR_IMPORT_EXTENSIONS", "md,sh!")
+    with pytest.raises(ValidationError, match="sh!"):
+        _settings()
+    monkeypatch.setenv("BOR_IMPORT_EXTENSIONS", "md,../x")
+    with pytest.raises(ValidationError, match=r"/x"):
         _settings()