chore(test): Centralize app_instance and mock_app fixtures in conftest.py

tests/conftest.py

@@ -8,11 +8,13 @@ import sys
 import datetime
 from pathlib import Path
 from typing import Generator, Any
+from unittest.mock import patch, MagicMock
 
 # Ensure project root is in path
 sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
 
 import ai_client
+from gui_2 import App
 
 @pytest.fixture(autouse=True)
 def reset_ai_client() -> Generator[None, None, None]:
@@ -22,6 +24,43 @@ def reset_ai_client() -> Generator[None, None, None]:
  ai_client.set_provider("gemini", "gemini-2.5-flash-lite")
  yield
 
+@pytest.fixture
+def app_instance() -> Generator[App, None, None]:
+ """
+ Centralized App instance with all external side effects mocked.
+ Matches the pattern used in test_token_viz.py and test_gui_phase4.py.
+ """
+ with (
+  patch('gui_2.load_config', return_value={
+   'ai': {'provider': 'gemini', 'model': 'gemini-2.5-flash-lite'},
+   'projects': {'paths': [], 'active': ''},
+   'gui': {'show_windows': {}}
+  }),
+  patch('gui_2.save_config'),
+  patch('gui_2.project_manager'),
+  patch('gui_2.session_logger'),
+  patch('gui_2.immapp.run'),
+  patch.object(App, '_load_active_project'),
+  patch.object(App, '_fetch_models'),
+  patch.object(App, '_load_fonts'),
+  patch.object(App, '_post_init'),
+  patch.object(App, '_prune_old_logs'),
+  patch.object(App, '_init_ai_and_hooks')
+ ):
+  app = App()
+  yield app
+  # Cleanup: Ensure asyncio loop is stopped
+  if hasattr(app, '_loop') and app._loop.is_running():
+   app._loop.call_soon_threadsafe(app._loop.stop)
+
+@pytest.fixture
+def mock_app(app_instance: App) -> App:
+ """
+ Simpler fixture returning a mocked App instance.
+ Reuses app_instance for automatic cleanup and consistent mocking.
+ """
+ return app_instance
+
 class VerificationLogger:
  """High-signal reporting for automated tests, inspired by Unreal Engine's diagnostic style."""
  def __init__(self, test_name: str, script_name: str):