feat: comprehensive test infrastructure improvements

- Fix unit test imports: add env setup in conftest.py before module imports
- Add 24 new auth router tests (RBAC, preferences, password validation)
- Add 16 new tests for litellm and chat_summary routers
- Apply black formatting and ruff linting across codebase
- Add pre-commit hooks configuration (black, ruff, file checks)
- Increase CI coverage threshold from 40% to 50%

Test Results:
- 206 tests passing (91 unit + 115 integration)
- Coverage: 58.79% on core modules
- auth.py: 57% → 85%, litellm.py: 23% → 87%, chat_summary.py: 41% → 100%
- auth_service: 96.51%, config: 100%, rbac: 93.48%

dashboard/backend/tests/conftest.py

@@ -1,12 +1,23 @@
 """
 Shared pytest fixtures for backend tests.
 """
-import os
+
 import json
-import pytest
+import os
 from datetime import timedelta
+from unittest.mock import AsyncMock, Mock, patch
+
+import pytest
 from fastapi.testclient import TestClient
-from unittest.mock import Mock, AsyncMock, patch
+
+# Set up environment variables before any imports during pytest collection
+os.environ.setdefault("SECRET_KEY", "test-secret-key-at-least-32-chars-long")
+os.environ.setdefault("ADMIN_USER", "testadmin")
+os.environ.setdefault("ADMIN_PASSWORD_HASH", "$pbkdf2-sha256$29000$N2YMIQQgBAAgxBgjhPD.vw$1234567890abcdef")
+os.environ.setdefault("VOLUME_ROOT", "/tmp/test-volume")
+os.environ.setdefault("DOCKER_HOST", "tcp://mock-docker:2375")
+os.environ.setdefault("GITEA_URL", "http://mock-gitea:3000")
+os.environ.setdefault("GITEA_TOKEN", "mock-token")
 
 
 @pytest.fixture
@@ -30,8 +41,10 @@ def mock_config(temp_volume_root, monkeypatch):
     monkeypatch.setenv("GITEA_TOKEN", "mock-token")
 
     # Reload config module to pick up new env vars
-    import config
     import importlib
+
+    import config
+
     importlib.reload(config)
 
     return config
@@ -41,12 +54,7 @@ def mock_config(temp_volume_root, monkeypatch):
 def temp_auth_file(temp_volume_root):
     """Create temporary auth.json file."""
     auth_file = os.path.join(temp_volume_root, "docker/nas-dashboard/auth.json")
-    data = {
-        "totp_secret": "",
-        "passkey_credentials": [],
-        "token_version": 0,
-        "last_totp_ts": 0
-    }
+    data = {"totp_secret": "", "passkey_credentials": [], "token_version": 0, "last_totp_ts": 0}
     with open(auth_file, "w") as f:
         json.dump(data, f)
     return auth_file
@@ -60,9 +68,9 @@ def temp_rbac_file(temp_volume_root):
         "role_defaults": {
             "admin": {"pages": "*", "sidebar_links": "*"},
             "member": {"pages": ["dashboard", "docker"], "sidebar_links": "*"},
-            "viewer": {"pages": ["dashboard"], "sidebar_links": ["dashboard"]}
+            "viewer": {"pages": ["dashboard"], "sidebar_links": ["dashboard"]},
         },
-        "user_overrides": {}
+        "user_overrides": {},
     }
     with open(rbac_file, "w") as f:
         json.dump(data, f)
@@ -73,16 +81,15 @@ def temp_rbac_file(temp_volume_root):
 def valid_access_token(mock_config):
     """Generate a valid access token for testing."""
     from auth_service import create_access_token
-    return create_access_token(
-        data={"sub": "testuser", "role": "admin"},
-        expires_delta=timedelta(minutes=30)
-    )
+
+    return create_access_token(data={"sub": "testuser", "role": "admin"}, expires_delta=timedelta(minutes=30))
 
 
 @pytest.fixture
 def valid_refresh_token(mock_config, temp_auth_file):
     """Generate a valid refresh token for testing."""
     from auth_service import create_refresh_token
+
     return create_refresh_token(data={"sub": "testuser", "role": "admin"})
 
 
@@ -90,10 +97,8 @@ def valid_refresh_token(mock_config, temp_auth_file):
 def expired_access_token(mock_config):
     """Generate an expired access token for testing."""
     from auth_service import create_access_token
-    return create_access_token(
-        data={"sub": "testuser", "role": "admin"},
-        expires_delta=timedelta(seconds=-1)
-    )
+
+    return create_access_token(data={"sub": "testuser", "role": "admin"}, expires_delta=timedelta(seconds=-1))
 
 
 @pytest.fixture
@@ -118,10 +123,7 @@ def mock_docker_client():
     container.status = "running"
     container.image = mock_image
     container.ports = {"80/tcp": [{"HostPort": "8080"}]}
-    container.attrs = {
-        "State": {"Health": {"Status": "healthy"}},
-        "Config": {"Image": "test-image:latest"}
-    }
+    container.attrs = {"State": {"Health": {"Status": "healthy"}}, "Config": {"Image": "test-image:latest"}}
     container.logs.return_value = b"test log line 1\ntest log line 2\n"
 
     client.containers.list.return_value = [container]
@@ -170,8 +172,13 @@ def mock_docker_client_factory():
                 image_tag="my-image:v1.0"
             )
     """
-    def _create_mock(container_name="test-container", container_status="running",
-                     image_tag="test-image:latest", container_id="abc123"):
+
+    def _create_mock(
+        container_name="test-container",
+        container_status="running",
+        image_tag="test-image:latest",
+        container_id="abc123",
+    ):
         client = Mock()
 
         # Mock container image
@@ -187,10 +194,7 @@ def mock_docker_client_factory():
         container.status = container_status
         container.image = mock_image
         container.ports = {"80/tcp": [{"HostPort": "8080"}]}
-        container.attrs = {
-            "State": {"Health": {"Status": "healthy"}},
-            "Config": {"Image": image_tag}
-        }
+        container.attrs = {"State": {"Health": {"Status": "healthy"}}, "Config": {"Image": image_tag}}
         container.logs.return_value = b"test log line 1\ntest log line 2\n"
 
         client.containers.list.return_value = [container]
@@ -229,8 +233,10 @@ def mock_httpx_client():
 def test_app(mock_config, temp_auth_file, temp_rbac_file, mock_docker_client):
     """Create FastAPI test client with mocked dependencies."""
     # Reload routers to pick up new config values
-    import routers.files
     import importlib
+
+    import routers.files
+
     importlib.reload(routers.files)
 
     # Patch Docker client before importing main
@@ -241,6 +247,7 @@ def test_app(mock_config, temp_auth_file, temp_rbac_file, mock_docker_client):
 
         with patch("slowapi.Limiter", return_value=mock_limiter):
             from main import app
+
             client = TestClient(app)
             yield client
 
@@ -258,14 +265,11 @@ def mock_rbac_data():
         "role_defaults": {
             "admin": {"pages": "*", "sidebar_links": "*"},
             "member": {"pages": ["dashboard", "docker", "files"], "sidebar_links": "*"},
-            "viewer": {"pages": ["dashboard"], "sidebar_links": ["dashboard"]}
+            "viewer": {"pages": ["dashboard"], "sidebar_links": ["dashboard"]},
         },
         "user_overrides": {
-            "customuser": {
-                "pages": ["dashboard", "docker"],
-                "sidebar_links": ["dashboard", "docker", "files"]
-            }
-        }
+            "customuser": {"pages": ["dashboard", "docker"], "sidebar_links": ["dashboard", "docker", "files"]}
+        },
     }