Agent Skills: test-driven-development

Use this skill when writing new features, fixing bugs, or adding test coverage. Enforces Red-Green-Refactor — write the test first, then the code. Trigger on "add tests", "write tests first", "TDD", "test this feature", "fix this bug" (reproduce with a failing test first), or when starting any new implementation. Prevents testing anti-patterns like over-mocking, test-per-method, and tests that pass but verify nothing.