fix: Address second code review findings (test isolation, frontend type safety)

backend/tests/api/test_api_auth.py

@@ -7,7 +7,9 @@ from ea_chatbot.history.models import User
 # We will need to mock HistoryManager and get_db dependencies later
 # For now, we define the expected behavior of the auth endpoints.
 
-client = TestClient(app)
+@pytest.fixture
+def client():
+    return TestClient(app)
 
 @pytest.fixture
 def mock_user():
@@ -19,7 +21,7 @@ def mock_user():
         theme_preference="light"
     )
 
-def test_register_user_success():
+def test_register_user_success(client):
     """Test successful user registration."""
     # We mock it where it is used in the router
     with patch("ea_chatbot.api.routers.auth.history_manager") as mock_hm:
@@ -34,7 +36,7 @@ def test_register_user_success():
         assert response.status_code == 201
         assert response.json()["email"] == "new@example.com"
 
-def test_login_success():
+def test_login_success(client):
     """Test successful login and JWT return."""
     with patch("ea_chatbot.api.routers.auth.history_manager") as mock_hm:
         mock_hm.authenticate_user.return_value = User(id="1", username="test@example.com")
@@ -48,7 +50,7 @@ def test_login_success():
         assert "access_token" in response.json()
         assert response.json()["token_type"] == "bearer"
 
-def test_login_invalid_credentials():
+def test_login_invalid_credentials(client):
     """Test login with wrong password."""
     with patch("ea_chatbot.api.routers.auth.history_manager") as mock_hm:
         mock_hm.authenticate_user.return_value = None
@@ -61,12 +63,12 @@ def test_login_invalid_credentials():
         assert response.status_code == 401
         assert "detail" in response.json()
 
-def test_protected_route_without_token():
+def test_protected_route_without_token(client):
     """Test that protected routes require a token."""
     response = client.get("/api/v1/auth/me")
     assert response.status_code == 401
 
-def test_oidc_login_redirect():
+def test_oidc_login_redirect(client):
     """Test that OIDC login returns a redirect URL and sets session cookie."""
     with patch("ea_chatbot.api.routers.auth.oidc_client") as mock_oidc:
         mock_oidc.get_auth_data.return_value = {
@@ -81,7 +83,7 @@ def test_oidc_login_redirect():
         assert response.json()["url"] == "https://oidc-provider.com/auth"
         assert "oidc_session" in response.cookies
 
-def test_oidc_callback_success():
+def test_oidc_callback_success(client):
     """Test successful OIDC callback and JWT issuance."""
     with patch("ea_chatbot.api.routers.auth.oidc_client") as mock_oidc, \
          patch("ea_chatbot.api.routers.auth.OIDCSession.decrypt") as mock_decrypt, \
@@ -105,7 +107,7 @@ def test_oidc_callback_success():
         assert response.status_code == 302
         assert "access_token" in response.cookies
 
-def test_get_me_success():
+def test_get_me_success(client):
     """Test getting current user with a valid token."""
     from ea_chatbot.api.utils import create_access_token
     token = create_access_token(data={"sub": "123"})