update: ruff check --fix

backend/tests/test_resources.py

@@ -7,12 +7,9 @@ from __future__ import annotations
 
 import datetime
 from types import SimpleNamespace
-from unittest.mock import AsyncMock, MagicMock
+from unittest.mock import MagicMock
 
 import pytest
-
-from types import SimpleNamespace
-
 from backend.resources import compute_jupyter_relative_path, resource_payload
 from backend.services.storage import _safe_file_name, _safe_path_segment