test(12-05): fix test_nextcloud_connect_persists + compose migration test path

- test_nextcloud_connect_persists: provider=nextcloud routes to NextcloudBackend
  (not WebDAVBackend) — add storage.nextcloud_backend.validate_cloud_url patch
  and use AsyncMock for asyncio.to_thread (plain return_value=True is not
  awaitable, swallowed by except → False). Test now passes HTTP 201.
- test_compose_migrations: skip module when docker-compose.yml is not found at
  the expected repo-root path (file is not mounted inside the backend container).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/tests/test_cloud.py

@@ -292,6 +292,42 @@ async def test_oauth_callback_invalid_state(async_client, db_session, monkeypatc
     app.state.redis = None
 
 
+async def test_nextcloud_connect_persists(async_client, db_session):
+    """POST /api/cloud/connections/webdav with provider=nextcloud creates a connection.
+
+    Regression for Phase 12 UAT blocker: POST /api/cloud/connections/webdav failed with
+    UndefinedColumn (display_name_override) when the DB was at revision 0005.
+    Uses unittest.mock.patch to stub SSRF validation and health probe at sys.modules level.
+    """
+    from unittest.mock import patch, AsyncMock
+
+    auth = await _create_user_and_token(db_session, role="user")
+
+    # provider=nextcloud routes to NextcloudBackend (not WebDAVBackend) in the
+    # cloud_backend_factory — patch validate_cloud_url in all namespaces that hold
+    # a from-import binding. asyncio.to_thread is accessed as a module attribute
+    # in both backends, so a single AsyncMock covers both.
+    with patch("api.cloud.connections.validate_cloud_url", return_value=None), \
+         patch("storage.webdav_backend.validate_cloud_url", return_value=None), \
+         patch("storage.nextcloud_backend.validate_cloud_url", return_value=None), \
+         patch("asyncio.to_thread", new_callable=AsyncMock, return_value=True):
+        resp = await async_client.post(
+            "/api/cloud/connections/webdav",
+            json={
+                "server_url": "https://nc.example.com/remote.php/dav",
+                "username": "testuser",
+                "password": "testpass",
+                "provider": "nextcloud",
+            },
+            headers=auth["headers"],
+        )
+
+    assert resp.status_code == 201, f"Unexpected: {resp.status_code} — {resp.text}"
+    data = resp.json()
+    assert data["provider"] == "nextcloud"
+    assert "credentials_enc" not in data
+
+
 async def test_webdav_connect_validates(async_client, db_session, monkeypatch):
     """POST /api/cloud/connections/webdav with localhost URL returns 422 (SSRF blocked)."""
     auth = await _create_user_and_token(db_session, role="user")

backend/tests/test_compose_migrations.py

@@ -21,6 +21,15 @@ import yaml
 REPO_ROOT = pathlib.Path(__file__).resolve().parents[2]
 COMPOSE_PATH = REPO_ROOT / "docker-compose.yml"
 
+# When running inside the Docker container the repo root is not mounted;
+# skip the whole module rather than erroring with FileNotFoundError.
+if not COMPOSE_PATH.exists():
+    pytest.skip(
+        f"docker-compose.yml not found at {COMPOSE_PATH} — "
+        "these static analysis tests must run from the host repo root, not inside a container.",
+        allow_module_level=True,
+    )
+
 APPLICATION_SERVICES = {"backend", "celery-worker", "celery-beat"}