tdd-workflow

Write user journeys first, generate test cases with Jest or Vitest, run them to confirm they fail, then implement minimal code to make them pass. After tests pass, refactor while keeping them green and verify at least 80% coverage.

Write unit tests for individual functions and component logic, integration tests for API endpoints and database operations, and Playwright E2E tests for critical user flows. All three levels together should reach the 80% coverage threshold.

Use jest.mock to replace the service module with stubbed functions returning resolved promises. For example, mock generateEmbedding to return a fixed 1536-dimension array and mock Redis vector search to return predefined similarity scores.

No. A valid RED state requires the test to compile and execute with a failure caused by the intended bug or missing implementation. Compile-time failures count only when the new test exercises the buggy code path directly.

Tests break when they rely on brittle CSS class selectors instead of semantic locators. Use role-based selectors, text matchers like button:has-text, or data-testid attributes, which remain stable across styling changes.

Create one commit after the failing test is validated as RED, one after the fix passes as GREEN, and an optional one after refactoring. Each commit must be reachable from the current HEAD on the active branch for the current task.