testing

# Testing Skill Comprehensive testing guidance covering: - **TDD Workflow**: Red → Green → Refactor cycle with practical examples - **Test Organization**: Unit / Integration / E2E test structure - **Framework Support**: pytest, Jest, JUnit5, xUnit, Google Test - **Mock Strategies**: Only mock external boundaries, not internal logic - **Coverage Requirements**: 80%+ with meaningful assertions ## When Loaded This skill is automatically injected when working with: - `/cc-best:dev` — Implementation with tests - `tdd-guide` agent — Test-driven development guidance - `build-error-resolver` agent — Fixing test failures ## Key Rules 1. **Tests first** — Write failing test before implementation 2. **AAA pattern** — Arrange, Act, Assert in every test 3. **No shared mutable state** — Each test is independent 4. **Descriptive names** — `test_<feature>_<scenario>_<expected>`