TDD Workflow

--- agent: agent description: Test-driven development cycle : write the test first, then implement --- # TDD Workflow Follow the RED → GREEN → IMPROVE cycle strictly. Do not write implementation code before a failing test exists. ## Cycle ### 1. RED : Write the failing test - Write a test that describes the desired behavior. - Run it. It must fail before continuing. - Use Arrange-Act-Assert structure. - Name tests descriptively: returns empty array when no items match filter, not test itemFilter. ### 2. GREEN : Minimal implementation - Write the minimum code needed to make the test pass. - Do not over-engineer at this stage. - Run the test again : it must pass. ### 3. IMPROVE : Refactor - Clean up duplication, naming, structure. - Keep all tests passing after each change. - Check coverage: target ≥ 80%. ## Test Layer Checklist - [ ] Unit : pure functions, utilities, isolated components - [ ] Integration : API endpoints, database operations, service boundaries - [ ] E2E : at least one critical user flow covered ## Quality Gates Before marking the feature done: - [ ] All tests pass - [ ] Coverage ≥ 80% - [ ] No skipped/commented-out tests - [ ] Edge cases covered: empty input, nulls, boundary values, error paths ## Anti-patterns to Avoid - Writing implementation before tests - Testing implementation details instead of behavior - Mocking too deeply (prefer integration tests over excessive mocks) - Assertions that always pass (expect(true).toBe(true))