M1-T03: unify data layer, models, deps and routes onto single app DB

Collapse the three data layers into one. app/db.py now exposes a single
Base, a cached engine bound to app_database_url with SQLite WAL enabled, and
get_engine/get_session_local/reset_db_caches/get_db_session. Delete
app/auth_db.py, app/poo_db.py and app/models/base.py. All models (auth,
config, public_ip, location, poo) inherit the one Base and register on a
single metadata. Dependencies converge to a single get_db; all routes use it.

Also update the alembic env.py files (app/location/poo) and tests that
imported the removed modules so the suite stays green, and drop the obsolete
test_legacy_style_location_db test whose flow (app reading a separate location
DB) no longer exists. Location/poo Alembic chains, adopt scripts and adoption
tests remain for M1-T04; config fields remain for M1-T05.

pytest 109 passed; ruff clean (pre-existing only); WAL verified; single
Base.metadata holds all seven tables.

tests/conftest.py

@@ -5,10 +5,8 @@ from alembic import command
 from alembic.config import Config
 from fastapi.testclient import TestClient
 from sqlalchemy import create_engine
-from sqlalchemy.orm import sessionmaker
 
-from app.auth_db import reset_auth_db_caches
-import app.db as app_db
+from app.db import reset_db_caches
 from app.config import get_settings
 from app.main import create_app
 
@@ -47,7 +45,7 @@ def test_database_urls(tmp_path: Path, monkeypatch: pytest.MonkeyPatch):
     monkeypatch.setenv("AUTH_BOOTSTRAP_PASSWORD", "test-password")
     monkeypatch.setenv("AUTH_COOKIE_SECURE_OVERRIDE", "false")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
     try:
         yield {
@@ -60,7 +58,7 @@ def test_database_urls(tmp_path: Path, monkeypatch: pytest.MonkeyPatch):
         }
     finally:
         get_settings.cache_clear()
-        reset_auth_db_caches()
+        reset_db_caches()
 
 
 @pytest.fixture
@@ -79,10 +77,10 @@ def ready_poo_database(test_database_urls):
 def auth_database(test_database_urls, monkeypatch: pytest.MonkeyPatch):
     database_url = test_database_urls["app_url"]
     command.upgrade(_make_app_alembic_config(database_url), "head")
-    reset_auth_db_caches()
+    reset_db_caches()
 
     yield test_database_urls
-    reset_auth_db_caches()
+    reset_db_caches()
 
 
 @pytest.fixture
@@ -97,46 +95,20 @@ def client(app):
 
 
 @pytest.fixture
-def location_client(
-    ready_location_database,
-    ready_poo_database,
-    auth_database,
-    monkeypatch: pytest.MonkeyPatch,
-):
-    database_url = ready_location_database["location_url"]
-
-    engine = create_engine(database_url, connect_args={"check_same_thread": False})
-    session_local = sessionmaker(bind=engine, autoflush=False, autocommit=False)
-
-    monkeypatch.setattr(app_db, "engine", engine)
-    monkeypatch.setattr(app_db, "SessionLocal", session_local)
-
+def location_client(ready_location_database, ready_poo_database, auth_database):
+    app_url = auth_database["app_url"]
+    engine = create_engine(app_url, connect_args={"check_same_thread": False})
     fastapi_app = create_app()
     with TestClient(fastapi_app) as client:
         yield client, engine
-
     engine.dispose()
 
 
 @pytest.fixture
-def poo_client(
-    ready_location_database,
-    ready_poo_database,
-    auth_database,
-    monkeypatch: pytest.MonkeyPatch,
-):
-    database_url = ready_poo_database["poo_url"]
-
-    engine = create_engine(database_url, connect_args={"check_same_thread": False})
-    session_local = sessionmaker(bind=engine, autoflush=False, autocommit=False)
-
-    import app.poo_db as poo_db
-
-    monkeypatch.setattr(poo_db, "poo_engine", engine)
-    monkeypatch.setattr(poo_db, "PooSessionLocal", session_local)
-
+def poo_client(ready_location_database, ready_poo_database, auth_database):
+    app_url = auth_database["app_url"]
+    engine = create_engine(app_url, connect_args={"check_same_thread": False})
     fastapi_app = create_app()
     with TestClient(fastapi_app) as client:
         yield client, engine
-
     engine.dispose()

tests/test_app.py

@@ -5,7 +5,7 @@ import pytest
 from alembic import command
 from fastapi.testclient import TestClient
 
-from app.auth_db import reset_auth_db_caches
+from app.db import reset_db_caches
 from app.config import get_settings
 from app.main import create_app
 from scripts.app_db_adopt import APP_BASELINE_REVISION, adopt_or_initialize_app_db
@@ -49,7 +49,7 @@ def test_app_start_fails_when_app_db_missing(tmp_path, monkeypatch: pytest.Monke
     monkeypatch.setenv("LOCATION_DATABASE_URL", f"sqlite:///{location_database_path}")
     monkeypatch.setenv("POO_DATABASE_URL", f"sqlite:///{poo_database_path}")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
     app = create_app()
     with pytest.raises(RuntimeError, match="Run 'python scripts/app_db_adopt.py' first"):
@@ -58,7 +58,7 @@ def test_app_start_fails_when_app_db_missing(tmp_path, monkeypatch: pytest.Monke
     assert not missing_app_path.exists()
 
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
 
 def test_app_db_adoption_initializes_new_database(tmp_path) -> None:
@@ -108,7 +108,7 @@ def test_app_start_seeds_missing_config_from_env_without_overwriting_existing_va
     monkeypatch.setenv("LOCATION_DATABASE_URL", f"sqlite:///{location_database_path}")
     monkeypatch.setenv("POO_DATABASE_URL", f"sqlite:///{poo_database_path}")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
     app = create_app()
     anyio.run(_run_lifespan, app)
@@ -124,7 +124,7 @@ def test_app_start_seeds_missing_config_from_env_without_overwriting_existing_va
     assert rows["AUTH_SESSION_COOKIE_NAME"] == "home_automation_session"
 
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
 
 def test_app_start_syncs_app_hostname_from_env_even_when_db_has_old_value(
@@ -152,7 +152,7 @@ def test_app_start_syncs_app_hostname_from_env_even_when_db_has_old_value(
     monkeypatch.setenv("LOCATION_DATABASE_URL", f"sqlite:///{location_database_path}")
     monkeypatch.setenv("POO_DATABASE_URL", f"sqlite:///{poo_database_path}")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
     app = create_app()
     anyio.run(_run_lifespan, app)
@@ -166,7 +166,7 @@ def test_app_start_syncs_app_hostname_from_env_even_when_db_has_old_value(
     assert rows["APP_HOSTNAME"] == "new.example.com"
 
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
 
 def test_app_start_fails_when_location_db_missing(
@@ -182,14 +182,14 @@ def test_app_start_fails_when_location_db_missing(
     monkeypatch.setenv("LOCATION_DATABASE_URL", f"sqlite:///{tmp_path / 'missing.db'}")
     monkeypatch.setenv("POO_DATABASE_URL", f"sqlite:///{poo_database_path}")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
     app = create_app()
     with pytest.raises(RuntimeError, match="Run 'python scripts/location_db_adopt.py' first"):
         anyio.run(_run_lifespan, app)
 
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
 
 def test_app_start_fails_when_location_db_exists_but_is_not_adopted(
@@ -223,14 +223,14 @@ def test_app_start_fails_when_location_db_exists_but_is_not_adopted(
     monkeypatch.setenv("LOCATION_DATABASE_URL", f"sqlite:///{database_path}")
     monkeypatch.setenv("POO_DATABASE_URL", f"sqlite:///{poo_database_path}")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
     app = create_app()
     with pytest.raises(RuntimeError, match="is not yet Alembic-managed"):
         anyio.run(_run_lifespan, app)
 
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
 
 def test_app_start_fails_when_location_db_revision_mismatches(
@@ -254,11 +254,11 @@ def test_app_start_fails_when_location_db_revision_mismatches(
     monkeypatch.setenv("LOCATION_DATABASE_URL", f"sqlite:///{database_path}")
     monkeypatch.setenv("POO_DATABASE_URL", f"sqlite:///{poo_database_path}")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
     app = create_app()
     with pytest.raises(RuntimeError, match="Location DB revision mismatch"):
         anyio.run(_run_lifespan, app)
 
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()

tests/test_auth.py

@@ -4,7 +4,7 @@ from pathlib import Path
 
 from fastapi.testclient import TestClient
 
-from app.auth_db import reset_auth_db_caches
+from app.db import reset_db_caches
 from app.config import get_settings
 from app.main import create_app
 
@@ -205,7 +205,7 @@ def test_config_page_shows_ticktick_oauth_link_when_ticktick_is_configured(
     monkeypatch.setenv("TICKTICK_CLIENT_ID", "ticktick-client-id")
     monkeypatch.setenv("TICKTICK_CLIENT_SECRET", "ticktick-client-secret")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
     with TestClient(create_app()) as client:
         login_page = client.get("/login")

tests/test_deployment.py

@@ -6,7 +6,7 @@ import pytest
 import yaml
 from alembic import command
 
-from app.auth_db import reset_auth_db_caches
+from app.db import reset_db_caches
 from app.config import get_settings
 from app.main import create_app
 from scripts.app_db_adopt import APP_BASELINE_REVISION
@@ -41,7 +41,7 @@ def _configure_database_env(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) ->
     monkeypatch.setenv("AUTH_BOOTSTRAP_PASSWORD", "test-password")
     monkeypatch.setenv("AUTH_COOKIE_SECURE_OVERRIDE", "false")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
     return {
         "app_path": app_path,
@@ -165,7 +165,7 @@ def test_migration_runner_initializes_and_is_idempotent(
         conn.close()
 
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
 
 def test_migration_runner_adopts_legacy_sqlite_without_data_loss(
@@ -194,7 +194,7 @@ def test_migration_runner_adopts_legacy_sqlite_without_data_loss(
         conn.close()
 
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
 
 def test_app_startup_still_fails_closed_without_running_adoption(
@@ -212,4 +212,4 @@ def test_app_startup_still_fails_closed_without_running_adoption(
     assert not Path(missing_app_path).exists()
 
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()

tests/test_homeassistant_inbound.py

@@ -1,7 +1,5 @@
 from sqlalchemy import text
 
-import app.db as app_db
-import app.poo_db as poo_db
 from app.config import Settings, get_settings
 from app.dependencies import get_app_settings, get_homeassistant_client
 from app.main import create_app
@@ -161,42 +159,24 @@ def test_homeassistant_publish_poo_get_latest_publishes_latest_status(
     ready_location_database,
     ready_poo_database,
     auth_database,
-    monkeypatch,
 ) -> None:
-    location_engine = app_db.create_engine(
-        ready_location_database["location_url"],
-        connect_args={"check_same_thread": False},
-    )
-    location_session_local = app_db.sessionmaker(
-        bind=location_engine,
-        autoflush=False,
-        autocommit=False,
-    )
-    poo_engine = poo_db.create_engine(
-        ready_poo_database["poo_url"],
-        connect_args={"check_same_thread": False},
-    )
-    poo_session_local = poo_db.sessionmaker(
-        bind=poo_engine,
-        autoflush=False,
-        autocommit=False,
-    )
+    from fastapi.testclient import TestClient
+    from sqlalchemy import create_engine
+
+    app_url = auth_database["app_url"]
+    engine = create_engine(app_url, connect_args={"check_same_thread": False})
+
     fake_ha = _FakeHomeAssistantClient()
     settings = Settings(
         poo_sensor_entity_name="sensor.test_poo_status",
         poo_sensor_friendly_name="Poo Status",
     )
 
-    monkeypatch.setattr(app_db, "engine", location_engine)
-    monkeypatch.setattr(app_db, "SessionLocal", location_session_local)
-    monkeypatch.setattr(poo_db, "poo_engine", poo_engine)
-    monkeypatch.setattr(poo_db, "PooSessionLocal", poo_session_local)
-
     test_app = create_app()
     test_app.dependency_overrides[get_homeassistant_client] = lambda: fake_ha
     test_app.dependency_overrides[get_app_settings] = lambda: settings
 
-    with poo_engine.begin() as conn:
+    with engine.begin() as conn:
         conn.execute(
             text(
                 "INSERT INTO poo_records (timestamp, status, latitude, longitude) "
@@ -211,8 +191,6 @@ def test_homeassistant_publish_poo_get_latest_publishes_latest_status(
         )
 
     try:
-        from fastapi.testclient import TestClient
-
         with TestClient(test_app) as client:
             response = client.post(
                 "/homeassistant/publish",
@@ -233,52 +211,27 @@ def test_homeassistant_publish_poo_get_latest_publishes_latest_status(
     finally:
         test_app.dependency_overrides.clear()
         get_settings.cache_clear()
-        location_engine.dispose()
-        poo_engine.dispose()
+        engine.dispose()
 
 
 def test_homeassistant_publish_returns_internal_error_for_unknown_poo_action(
     ready_location_database,
     ready_poo_database,
     auth_database,
-    monkeypatch,
 ) -> None:
-    location_engine = app_db.create_engine(
-        ready_location_database["location_url"],
-        connect_args={"check_same_thread": False},
-    )
-    location_session_local = app_db.sessionmaker(
-        bind=location_engine,
-        autoflush=False,
-        autocommit=False,
-    )
-    poo_engine = poo_db.create_engine(
-        ready_poo_database["poo_url"],
-        connect_args={"check_same_thread": False},
-    )
-    poo_session_local = poo_db.sessionmaker(
-        bind=poo_engine,
-        autoflush=False,
-        autocommit=False,
-    )
+    from fastapi.testclient import TestClient
+
     fake_ha = _FakeHomeAssistantClient()
     settings = Settings(
         poo_sensor_entity_name="sensor.test_poo_status",
         poo_sensor_friendly_name="Poo Status",
     )
 
-    monkeypatch.setattr(app_db, "engine", location_engine)
-    monkeypatch.setattr(app_db, "SessionLocal", location_session_local)
-    monkeypatch.setattr(poo_db, "poo_engine", poo_engine)
-    monkeypatch.setattr(poo_db, "PooSessionLocal", poo_session_local)
-
     test_app = create_app()
     test_app.dependency_overrides[get_homeassistant_client] = lambda: fake_ha
     test_app.dependency_overrides[get_app_settings] = lambda: settings
 
     try:
-        from fastapi.testclient import TestClient
-
         with TestClient(test_app) as client:
             response = client.post(
                 "/homeassistant/publish",
@@ -295,8 +248,6 @@ def test_homeassistant_publish_returns_internal_error_for_unknown_poo_action(
     finally:
         test_app.dependency_overrides.clear()
         get_settings.cache_clear()
-        location_engine.dispose()
-        poo_engine.dispose()
 
 
 def test_homeassistant_publish_returns_not_implemented_for_unknown_location_action(

tests/test_location.py

@@ -5,18 +5,14 @@ import sqlite3
 import pytest
 from alembic import command
 from alembic.config import Config
-from sqlalchemy import create_engine, text
-from sqlalchemy.orm import sessionmaker
+from sqlalchemy import text
 
-import app.db as app_db
-from app.main import create_app
 from scripts.location_db_adopt import (
     EXPECTED_USER_VERSION,
     LOCATION_BASELINE_REVISION,
     LocationDatabaseAdoptionError,
     adopt_or_initialize_location_db,
 )
-from tests.conftest import _make_app_alembic_config, _make_poo_alembic_config
 
 
 def _make_alembic_config(database_url: str) -> Config:
@@ -197,66 +193,6 @@ def test_location_record_endpoint_defaults_invalid_altitude_to_zero(location_cli
     assert row.altitude == pytest.approx(0.0)
 
 
-def test_legacy_style_location_db_can_be_stamped_and_adopted(
-    test_database_urls, monkeypatch: pytest.MonkeyPatch
-) -> None:
-    app_database_url = test_database_urls["app_url"]
-    database_path = test_database_urls["location_path"]
-    database_url = test_database_urls["location_url"]
-    poo_database_url = test_database_urls["poo_url"]
-
-    conn = sqlite3.connect(database_path)
-    conn.execute(
-        """
-        CREATE TABLE location (
-          person TEXT NOT NULL,
-          datetime TEXT NOT NULL,
-          latitude REAL NOT NULL,
-          longitude REAL NOT NULL,
-          altitude REAL,
-          PRIMARY KEY (person, datetime)
-        )
-        """
-    )
-    conn.execute("PRAGMA user_version = 2")
-    conn.commit()
-    conn.close()
-
-    command.upgrade(_make_app_alembic_config(app_database_url), "head")
-    command.stamp(_make_alembic_config(database_url), LOCATION_BASELINE_REVISION)
-    command.upgrade(_make_poo_alembic_config(poo_database_url), "head")
-
-    engine = create_engine(database_url, connect_args={"check_same_thread": False})
-    session_local = sessionmaker(bind=engine, autoflush=False, autocommit=False)
-    monkeypatch.setattr(app_db, "engine", engine)
-    monkeypatch.setattr(app_db, "SessionLocal", session_local)
-
-    from fastapi.testclient import TestClient
-
-    fastapi_app = create_app()
-    with TestClient(fastapi_app) as client:
-        response = client.post(
-            "/location/record",
-            json={
-                "person": "legacy-user",
-                "latitude": "12.3",
-                "longitude": "45.6",
-                "altitude": "7.8",
-            },
-        )
-
-    assert response.status_code == 200
-
-    with engine.connect() as db_conn:
-        revision = db_conn.execute(text("SELECT version_num FROM alembic_version")).scalar_one()
-        row_count = db_conn.execute(text("SELECT COUNT(*) FROM location")).scalar_one()
-
-    assert revision == LOCATION_BASELINE_REVISION
-    assert row_count == 1
-
-    engine.dispose()
-
-
 def test_location_db_adoption_initializes_new_db(tmp_path: Path) -> None:
     database_path = tmp_path / "new_location.db"
     result = adopt_or_initialize_location_db(f"sqlite:///{database_path}")

tests/test_ticktick.py

@@ -6,7 +6,7 @@ from urllib.parse import parse_qs, urlparse
 import pytest
 from fastapi.testclient import TestClient
 
-from app.auth_db import reset_auth_db_caches
+from app.db import reset_db_caches
 from app.config import Settings, get_settings
 from app.integrations.ticktick import (
     AUTH_SCOPE,
@@ -221,7 +221,7 @@ def test_homeassistant_publish_creates_ticktick_action_task(
     monkeypatch.setenv("TICKTICK_TOKEN", "ticktick-access-token")
     monkeypatch.setenv("HOME_ASSISTANT_ACTION_TASK_PROJECT_ID", "project-123")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
 
     captured = {"calls": []}
 
@@ -265,7 +265,7 @@ def test_ticktick_auth_start_redirects_authenticated_user(
     monkeypatch.setenv("TICKTICK_CLIENT_ID", "ticktick-client-id")
     monkeypatch.setenv("TICKTICK_CLIENT_SECRET", "ticktick-client-secret")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
     monkeypatch.setattr("app.integrations.ticktick.secrets.token_hex", lambda _: "state-redirect")
 
     with TestClient(create_app()) as client:
@@ -301,7 +301,7 @@ def test_ticktick_auth_callback_persists_token(
     monkeypatch.setenv("TICKTICK_CLIENT_ID", "ticktick-client-id")
     monkeypatch.setenv("TICKTICK_CLIENT_SECRET", "ticktick-client-secret")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
     default_auth_state_store.pending_state = "callback-state"
 
     def fake_urlopen(req, timeout):
@@ -342,7 +342,7 @@ def test_ticktick_auth_callback_redirects_on_invalid_state(
     monkeypatch.setenv("TICKTICK_CLIENT_ID", "ticktick-client-id")
     monkeypatch.setenv("TICKTICK_CLIENT_SECRET", "ticktick-client-secret")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
     default_auth_state_store.pending_state = "expected-state"
 
     with TestClient(create_app()) as client:
@@ -366,7 +366,7 @@ def test_ticktick_auth_callback_redirects_when_token_exchange_fails(
     monkeypatch.setenv("TICKTICK_CLIENT_ID", "ticktick-client-id")
     monkeypatch.setenv("TICKTICK_CLIENT_SECRET", "ticktick-client-secret")
     get_settings.cache_clear()
-    reset_auth_db_caches()
+    reset_db_caches()
     default_auth_state_store.pending_state = "callback-state"
 
     def fake_urlopen(req, timeout):