MCP Agile Flow

--- description: Apply vertical slicing with hybrid testing when developing modular features to balance independence and integration globs: **/modules/**/*.py alwaysApply: false --- # Vertical Slicing with Hybrid Testing ## Context - When developing modular features that can operate independently - When organizing code and tests for complex applications - When balancing component independence with system integration needs - When enabling faster development cycles for individual modules ## Requirements - Structure modules as self-contained vertical slices with their own tests - Implement a hybrid testing approach matching test scope to test location - Place unit and module-integration tests within their module directory - Keep cross-module integration tests at the application level - Include a standalone mode for modules when applicable - Provide service mode toggles to switch between direct and API access - Document the test organization clearly with READMEs ## Examples <example> ✅ **Good Module Structure**: ``` modules/feature/ ├── app/ # Application code │ ├── components/ # UI components │ ├── pages/ # Page definitions │ └── utils/ # Utilities like API clients ├── service.py # Service layer ├── standalone.py # Standalone runner ├── tests/ # Test directory │ ├── unit/ # Unit tests for isolated components │ ├── integration/ # Tests within the module boundary │ ├── conftest.py # Module-specific test fixtures │ └── README.md # Documents test organization └── README.md # Module documentation ``` ✅ **Good Test Organization**: ```python # In modules/feature/tests/unit/test_parser.py - Unit test def test_parser_handles_empty_input(): """Test parser handles empty input gracefully.""" assert parse_input("") == [] # In modules/feature/tests/integration/test_service.py - Module integration def test_service_stores_parsed_data(db_session): """Test service stores parsed data in the database.""" service = FeatureService(session=db_session) result = service.process_and_store("raw data") assert db_session.query(DataModel).count() == 1 # In tests/modules/feature/test_api.py - Cross-module integration def test_feature_api_requires_authentication(client): """Test feature API endpoints require authentication.""" response = client.get("/api/feature/data") assert response.status_code == 401 # Unauthorized ``` </example> <example type="invalid"> ❌ **Bad Module Structure**: ``` modules/feature/ ├── components.py # UI components with no organization ├── service.py # Service with direct imports from other modules └── utils.py # Mixed utilities tests/ └── test_feature.py # All tests mixed together ``` ❌ **Bad Test Organization**: ```python # All tests at the application level regardless of scope def test_parser(): # Unit test in wrong location pass def test_database_integration(): # Module test in wrong location pass ``` ❌ **Bad Service Access**: ```python # Hardcoded service type with no toggle def get_service(): return DirectService() # No way to switch to API mode for testing ``` </example> ## Critical Rules - Make modules self-contained with clear boundaries - Keep unit and module integration tests with their module - Move cross-module tests to application-level test directories - Implement service mode toggles for API vs. direct service access - Create standalone mode for independent module usage - Document test organization with READMEs - Follow standard naming conventions for test files - Ensure test fixtures are available at the appropriate levels