testing-strategies

Comprehensive testing strategy design covering unit, integration, E2E testing, and TDD practices. Ratio guide : Given-When-Then pattern : Mocking strategy : API endpoint tests : Red-Green-Refactor Cycle : #testing #test-strategy #TDD #unit-test #integration-test #E2E #code-quality - Implements test pyramid structure with recommended ratios: 70% unit tests, 20% integration, 10% E2E tests - Provides Given-When-Then patterns for unit testing, mocking strategies for external dependencies, and API endpoint testing examples - Includes E2E testing guidance using Playwright for complete user flow validation and TDD red-green-refactor cycle methodology - Covers CI/CD integration, test isolation requirements, and best practices including AAA pattern, deterministic tests, and edge case handling - New project : define a testing strategy - Quality issues : bugs happen frequently - Before refactoring : build a safety net - CI/CD setup : automated tests - Unit: 70% - Integration: 20% - E2E: 10% - Test isolation : each test is independent - Fast feedback : unit tests should be fast (<1 min) - Deterministic : same input → same result - Test dependencies : do not let test A depend on test B - Production DB : do not use a real DB in tests - Sleep/Timeout : avoid time-based tests - AAA pattern : Arrange-Act-Assert - Test names : "should ... when ..." - Edge Cases : boundary values, null, empty...