regression-io/claude-config-plugins/testing

Testing Rules

Test-Driven Development

• Write tests BEFORE implementation (Red-Green-Refactor)
• Each test verifies a single behavior
• Tests must be independent - no test depends on another
• Keep tests small: ideally <10 assertions

Coverage Requirements

• New features must include tests
• Bug fixes must include regression tests
• Aim for >80% coverage, >90% for critical paths
• Coverage measures behavior testing, not just line coverage

Test Quality (FIRST)

• Fast: Tests run in milliseconds
• Isolated: No shared state between tests
• Repeatable: Same results every run, no flakiness
• Self-checking: Clear pass/fail without manual verification
• Timely: Written close to implementation

Test Pyramid

• 70% Unit tests (fast, isolated)
• 20% Integration tests (component interactions)
• 10% E2E tests (user workflows)
• Don't test implementation details - test behavior

Naming & Organization

• Pattern: test_[unit]_[scenario]_[expected]
• Example: test_validateEmail_invalidFormat_returnsFalse
• One test file per production module
• Group related tests with describe/context blocks

Assertions & Mocking

• One logical assertion per test
• Use specific assertion messages
• Mock external services and dependencies
• Use factories for complex test objects