moai-ref-testing-pyramid

The recommended distribution is 70% unit tests, 20% integration tests, and 10% E2E tests. Unit tests run under 100ms each, integration tests take 1-5 seconds, and E2E tests cover only critical user journeys.

AAA stands for Arrange, Act, Assert: set up test data and preconditions, execute the function under test, then verify the outcome. This structure keeps tests readable and separates setup from verification logic.

Coverage targets depend on context: 95%+ for critical business logic, 90%+ for API endpoints, 85%+ for utilities, 80%+ for UI components, and 60%+ for glue code. Generated code requires no testing.

Yes, mock at boundaries such as databases and APIs to keep unit tests fast and deterministic. Reserve real dependencies for integration tests using tools like testcontainers or in-memory databases.

Coverage measures execution, not correctness. A test that runs code without meaningful assertions provides zero value, so branch coverage and mutation scores are better quality indicators than raw line coverage.

Fix the flakiness or quarantine the test with a tracking issue. Flaky tests erode trust in the entire suite, and the target flaky rate should stay below 1% based on CI history analysis.