Testing is crucial for maintaining code quality and preventing regressions. A balanced testing strategy includes multiple layers.
Unit Tests: Test individual functions and components in isolation. Fast, reliable, and easy to maintain. Target 80%+ coverage for critical business logic.
Integration Tests: Verify that multiple components work together correctly. Test API endpoints, database queries, and service integrations.
End-to-End Tests: Simulate real user workflows across the entire application. Use tools like Playwright or Cypress. Keep E2E tests focused on critical paths only.
Testing Pyramid: Many unit tests at the bottom, fewer integration tests in the middle, and even fewer E2E tests at the top.
Mocking: Mock external dependencies in unit tests. Use real dependencies in integration tests. Mock only what you do not control.
CI/CD Integration: Run tests automatically on every push. Block merges on test failures. Use test reports to track coverage trends over time.