fix(tests): isolate database and module state

tests/conftest.py

@@ -8,15 +8,12 @@ import pytest
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
-# Importing core.database below runs init_db() at import time, and its default
-# (sqlite:///./data/app.db) can't be opened in a clean worktree because SQLite
-# won't create the missing ./data parent dir - pytest then dies during
-# collection, before any test module loads. Default to an in-memory DB for the
-# test session so collection is deterministic and writes no repo-local
-# artifacts. An explicit DATABASE_URL (a real test/CI database) is preserved.
-# This only unblocks collection/import-time init; it does not provide a shared
-# file-backed DB across processes - tests needing that must set DATABASE_URL.
-os.environ.setdefault("DATABASE_URL", "sqlite:///:memory:")
+# core.database initializes its engine during import. Always isolate that
+# bootstrap from an inherited developer DATABASE_URL, before collection can
+# import it. Tests needing files own their disposable databases explicitly.
+# Restore the caller's environment when pytest's configuration is torn down.
+_database_environment = pytest.MonkeyPatch()
+_database_environment.setenv("DATABASE_URL", "sqlite:///:memory:")
 
 # Pre-import real heavy modules BEFORE any test file's module-level stubs can
 # replace them with MagicMock. Some test files (e.g. test_llm_core_sanitize_*)
@@ -101,6 +98,8 @@ def pytest_configure(config):
     unknown-mark warnings still surface genuine typos outside the taxonomy. This
     only registers marker names; it imports no production module.
     """
+    config.add_cleanup(_database_environment.undo)
+
     import pathlib
     from tests._taxonomy import discover_markers
 

tests/helpers/database.py

@@ -0,0 +1,51 @@
+"""Disposable databases for tests that exercise the real ORM and session manager."""
+
+from contextlib import contextmanager
+from tempfile import TemporaryDirectory
+
+import pytest
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+from sqlalchemy.pool import NullPool
+
+
+@contextmanager
+def disposable_database(tmp_path):
+    """Own the database file and engine; keep the canonical ORM classes intact."""
+    import core.database as database
+
+    with TemporaryDirectory(prefix="database-", dir=tmp_path) as directory:
+        engine = create_engine(
+            f"sqlite:///{directory}/test.db",
+            connect_args={"check_same_thread": False},
+            poolclass=NullPool,
+        )
+        try:
+            database.Base.metadata.create_all(engine)
+            yield sessionmaker(bind=engine, autoflush=False, autocommit=False)
+        finally:
+            engine.dispose()
+
+
+@contextmanager
+def isolated_session_database(tmp_path):
+    """Temporarily bind the real manager and database aliases without reloading.
+
+    Reloading core.database changes its ORM classes while existing imports keep
+    the old classes and factories. Patch only resource bindings instead, and
+    undo them before disposing the owned engine and removing its files.
+    """
+    import core.database as database
+    import core.session_manager as manager
+    import src.database as compatibility_database
+
+    with disposable_database(tmp_path) as factory:
+        engine = factory.kw["bind"]
+        with pytest.MonkeyPatch.context() as patcher:
+            patcher.setenv("DATABASE_URL", str(engine.url))
+            for module in (database, compatibility_database):
+                patcher.setattr(module, "DATABASE_URL", str(engine.url))
+                patcher.setattr(module, "engine", engine)
+                patcher.setattr(module, "SessionLocal", factory)
+            patcher.setattr(manager, "SessionLocal", factory)
+            yield manager.SessionManager(), database

tests/test_checkin_digest_owner_scope.py

@@ -5,23 +5,23 @@ check-in for one user pulled EVERY user's calendar events (summaries,
 locations) into their digest — a cross-tenant leak. Ownership lives on
 CalendarCal.owner; the query must join it, like routes/calendar_routes.
 """
-import tempfile
 import uuid
+import sys
 from datetime import datetime
 
 import pytest
-from sqlalchemy import create_engine
-from sqlalchemy.orm import sessionmaker
-from sqlalchemy.pool import NullPool
+from tests.helpers.database import disposable_database
 
-import core.database as cdb
 from core.database import CalendarEvent, CalendarCal
 from src.task_scheduler import _checkin_calendar_events
 
-_TMPDB = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_ENGINE = create_engine(f"sqlite:///{_TMPDB.name}", connect_args={"check_same_thread": False}, poolclass=NullPool)
-cdb.Base.metadata.create_all(_ENGINE)
-_TS = sessionmaker(bind=_ENGINE, autoflush=False, autocommit=False)
+
+@pytest.fixture(autouse=True)
+def _digest_database(tmp_path):
+    with disposable_database(tmp_path) as factory:
+        with pytest.MonkeyPatch.context() as patcher:
+            patcher.setattr(sys.modules[__name__], "_TS", factory, raising=False)
+            yield
 
 
 def _seed():

tests/test_database_test_isolation.py

@@ -0,0 +1,135 @@
+"""Guard database ownership at the helper and actual pytest lifecycle seams."""
+
+import os
+from pathlib import Path
+import subprocess
+import sys
+import textwrap
+
+import pytest
+
+from tests.helpers.database import isolated_session_database
+
+
+@pytest.mark.parametrize("fail_inside", [False, True])
+def test_session_database_restores_bindings_and_removes_files(tmp_path, fail_inside):
+    import core.database as database
+    import core.session_manager as manager
+    import src.database as compatibility_database
+    from core.models import ChatMessage
+
+    modules = (database, compatibility_database, manager)
+    names = ("DATABASE_URL", "engine", "SessionLocal", "Base", "Session", "ChatMessage")
+    before = [{name: getattr(module, name) for name in names if hasattr(module, name)}
+              for module in modules]
+    previous_url = os.environ.get("DATABASE_URL")
+    saved_manager_class = manager.SessionManager
+    saved_db_session = manager.DbSession
+    saved_db_message = manager.DbChatMessage
+    listener = database.set_sqlite_pragma
+
+    class IntentionalFailure(Exception):
+        pass
+
+    try:
+        with isolated_session_database(tmp_path) as (sm, db_module):
+            owned_path = Path(db_module.engine.url.database)
+            assert owned_path.is_file()
+            assert owned_path.is_relative_to(tmp_path)
+            assert db_module.Session is saved_db_session
+            assert db_module.ChatMessage is saved_db_message
+            assert sm.__class__ is saved_manager_class
+            assert compatibility_database.SessionLocal is manager.SessionLocal
+            sm.create_session(session_id="owned", name="t", endpoint_url="x",
+                              model="m", rag=False, owner="alice")
+            sm.add_message("owned", ChatMessage("user", "keep"))
+            sm.add_message("owned", ChatMessage("user", "remove"))
+            assert sm.truncate_messages("owned", 1)
+            with db_module.SessionLocal() as db:
+                assert db.query(saved_db_message).filter_by(session_id="owned").count() == 1
+                assert db.query(saved_db_session).filter_by(id="owned").one().message_count == 1
+            if fail_inside:
+                raise IntentionalFailure
+    except IntentionalFailure:
+        assert fail_inside
+
+    assert os.environ.get("DATABASE_URL") == previous_url
+    for module, bindings in zip(modules, before):
+        for name, value in bindings.items():
+            assert getattr(module, name) is value
+    assert database.set_sqlite_pragma is listener
+    assert manager.DbSession is saved_db_session
+    assert manager.DbChatMessage is saved_db_message
+    assert manager.SessionManager is saved_manager_class
+    assert not owned_path.parent.exists()
+
+    with isolated_session_database(tmp_path) as (sm, db_module):
+        assert db_module.engine.url.database != str(owned_path)
+        with pytest.raises(KeyError, match="Session owned not found"):
+            sm.get_session("owned")
+        with db_module.SessionLocal() as db:
+            assert db.query(saved_db_session).count() == 0
+
+
+@pytest.mark.parametrize("truncation_first", [True, False])
+def test_actual_tests_restore_process_state_and_ignore_inherited_database(tmp_path, truncation_first):
+    # An inherited developer URL must never be opened, even during collection.
+    inherited_db = tmp_path / "developer.db"
+    sentinel = b"a developer database must not be opened or initialized"
+    inherited_db.write_bytes(sentinel)
+    inherited_url = f"sqlite:///{inherited_db}"
+    truncation = "tests/test_truncate_message_count_regression.py"
+    owner = "tests/test_manage_tasks_owner_scope.py::test_edit_allowed_for_matching_owner"
+    manifest = [truncation, owner] if truncation_first else [owner, truncation]
+    script = textwrap.dedent('''
+        import os
+        import sys
+        import pytest
+
+        def snapshot():
+            import core
+            import src
+            import core.database as db
+            import core.session_manager as sm
+            import src.database as compat
+            return (
+                os.environ.get("DATABASE_URL"),
+                sys.modules["core.database"], core.database,
+                sys.modules["core.session_manager"], core.session_manager,
+                sys.modules["src.database"], src.database,
+                db.DATABASE_URL, db.engine, db.SessionLocal, db.Base,
+                db.Session, db.ChatMessage, db.ScheduledTask, db.set_sqlite_pragma,
+                compat.DATABASE_URL, compat.engine, compat.SessionLocal,
+                compat.Session, compat.ChatMessage,
+                sm.SessionLocal, sm.DbSession, sm.DbChatMessage, sm.SessionManager,
+            )
+
+        class StateGuard:
+            def pytest_sessionstart(self):
+                self.initial = snapshot()
+                assert self.initial[0] == "sqlite:///:memory:"
+
+            def pytest_collection_finish(self):
+                assert snapshot() == self.initial, "collection changed database bindings"
+
+            @pytest.hookimpl(hookwrapper=True, tryfirst=True)
+            def pytest_runtest_teardown(self):
+                yield
+                assert snapshot() == self.initial, "test leaked database or module state"
+
+        inherited_url = os.environ["DATABASE_URL"]
+        result = pytest.main(["-q", "-p", "no:cacheprovider", *sys.argv[1:]],
+                             plugins=[StateGuard()])
+        assert os.environ["DATABASE_URL"] == inherited_url
+        raise SystemExit(result)
+    ''')
+    result = subprocess.run(
+        [sys.executable, "-c", script, *manifest],
+        cwd=Path(__file__).resolve().parents[1],
+        env={**os.environ, "DATABASE_URL": inherited_url},
+        capture_output=True, text=True, timeout=60,
+    )
+    assert result.returncode == 0, result.stdout + result.stderr
+    assert "3 passed" in result.stdout
+    assert inherited_db.read_bytes() == sentinel
+    assert sorted(path.name for path in tmp_path.iterdir()) == ["developer.db"]

tests/test_document_session_owner_scope.py

@@ -5,36 +5,31 @@ document route tests. This keeps coverage on the real closures without spinning
 up middleware.
 """
 
-import tempfile
 import uuid
+import sys
 from types import SimpleNamespace
 from unittest.mock import MagicMock
 
 import pytest
 from fastapi import HTTPException
-from sqlalchemy import create_engine
-from sqlalchemy.orm import sessionmaker
-from sqlalchemy.pool import NullPool
-
+from tests.helpers.database import disposable_database
 from tests.helpers.import_state import clear_fake_database_modules
 
 clear_fake_database_modules()
 
-import core.database as cdb
 import routes.document_routes as droutes
 from core.database import Document
 from core.database import Session as DbSession
 from routes.document_helpers import DocumentPatch
 from routes.document_helpers import _owner_session_filter
 
-_TMPDB = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_ENGINE = create_engine(
-    f"sqlite:///{_TMPDB.name}",
-    connect_args={"check_same_thread": False},
-    poolclass=NullPool,
-)
-cdb.Base.metadata.create_all(_ENGINE)
-_TS = sessionmaker(bind=_ENGINE, autoflush=False, autocommit=False)
+
+@pytest.fixture(autouse=True)
+def _document_database(tmp_path):
+    with disposable_database(tmp_path) as factory:
+        with pytest.MonkeyPatch.context() as patcher:
+            patcher.setattr(sys.modules[__name__], "_TS", factory, raising=False)
+            yield
 
 
 def _req(user="alice"):

tests/test_gallery_owner_filter_single_user.py

@@ -4,22 +4,22 @@ When AUTH_ENABLED=false, get_current_user returns None and gallery routes should
 stay all-visible. When AUTH_ENABLED=true and no current user resolves, the same
 None means an anonymous caller and gallery queries must fail closed.
 """
-import tempfile
 import uuid
+import sys
 
 import pytest
-from sqlalchemy import create_engine
-from sqlalchemy.orm import sessionmaker
-from sqlalchemy.pool import NullPool
+from tests.helpers.database import disposable_database
 
-import core.database as cdb
 from core.database import GalleryImage
 from routes.gallery_helpers import _owner_filter
 
-_TMPDB = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_ENGINE = create_engine(f"sqlite:///{_TMPDB.name}", connect_args={"check_same_thread": False}, poolclass=NullPool)
-cdb.Base.metadata.create_all(_ENGINE)
-_TS = sessionmaker(bind=_ENGINE, autoflush=False, autocommit=False)
+
+@pytest.fixture(autouse=True)
+def _gallery_database(tmp_path):
+    with disposable_database(tmp_path) as factory:
+        with pytest.MonkeyPatch.context() as patcher:
+            patcher.setattr(sys.modules[__name__], "_TS", factory, raising=False)
+            yield
 
 
 def _seed(*owners):

tests/test_manage_tasks_owner_scope.py

@@ -12,14 +12,12 @@ permissive than the reader.
 """
 
 import json
-import tempfile
+import sys
 from datetime import datetime
 
 import pytest
-from sqlalchemy import create_engine
-from sqlalchemy.orm import sessionmaker
-from sqlalchemy.pool import NullPool
 
+from tests.helpers.database import disposable_database
 from tests.helpers.import_state import clear_fake_database_modules
 
 clear_fake_database_modules()
@@ -28,17 +26,16 @@ import core.database as cdb
 from core.database import ScheduledTask
 from src.tools.system import do_manage_tasks
 
-_TMPDB = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-_ENGINE = create_engine(
-    f"sqlite:///{_TMPDB.name}",
-    connect_args={"check_same_thread": False},
-    poolclass=NullPool,
-)
-cdb.Base.metadata.create_all(_ENGINE)
-_TS = sessionmaker(bind=_ENGINE, autoflush=False, autocommit=False)
-# do_manage_tasks does `from core.database import SessionLocal` at call time,
-# so patching the module attribute is enough to point it at the temp DB.
-cdb.SessionLocal = _TS
+
+@pytest.fixture(autouse=True)
+def _task_database(tmp_path):
+    # do_manage_tasks imports SessionLocal at call time. Own this binding for
+    # just one test, including helpers that seed and inspect its rows.
+    with disposable_database(tmp_path) as factory:
+        with pytest.MonkeyPatch.context() as patcher:
+            patcher.setattr(sys.modules[__name__], "_TS", factory, raising=False)
+            patcher.setattr(cdb, "SessionLocal", factory)
+            yield
 
 
 def _seed(task_id, owner, *, name=None):

tests/test_truncate_message_count_regression.py

@@ -9,30 +9,21 @@ inconsistent with the actual rows. get_session relies on message_count>0 to
 decide whether to lazily hydrate from the DB, so an inflated count is a latent
 correctness hazard.
 """
-import os
-import tempfile
+import pytest
+
+from tests.helpers.database import isolated_session_database
 
 
-def _make_manager():
-    db_fd, db_path = tempfile.mkstemp(suffix=".db")
-    os.close(db_fd)
-    os.environ["DATABASE_URL"] = f"sqlite:///{db_path}"
-
-    # Import after DATABASE_URL is set so the engine binds to the temp DB.
-    import importlib
-    import core.database as database
-    importlib.reload(database)
-    database.Base.metadata.create_all(bind=database.engine)
-
-    import core.session_manager as sm_mod
-    importlib.reload(sm_mod)
-    return sm_mod.SessionManager(), database, sm_mod
+@pytest.fixture
+def manager_database(tmp_path):
+    with isolated_session_database(tmp_path) as resources:
+        yield resources
 
 
-def test_truncate_keep_count_exceeds_total_does_not_inflate_count():
+def test_truncate_keep_count_exceeds_total_does_not_inflate_count(manager_database):
     from core.models import ChatMessage
 
-    sm, database, sm_mod = _make_manager()
+    sm, database = manager_database
     sid = "short-session"
     sm.create_session(session_id=sid, name="t", endpoint_url="x",
                       model="m", rag=False, owner="u")
@@ -59,10 +50,10 @@ def test_truncate_keep_count_exceeds_total_does_not_inflate_count():
         db.close()
 
 
-def test_truncate_keeps_history_alias_for_context_messages():
+def test_truncate_keeps_history_alias_for_context_messages(manager_database):
     from core.models import ChatMessage
 
-    sm, database, sm_mod = _make_manager()
+    sm, database = manager_database
     sid = "alias-after-truncate"
     sm.create_session(session_id=sid, name="t", endpoint_url="x",
                       model="m", rag=False, owner="u")