TDD Skill
When to use this skill
- new features that can be unit tested
- bug fixes (always add a regression test if practical)
- refactors (protect behavior with tests first)
Rules
- Prefer red -> green -> refactor.
- If tests are hard, still add verification: minimal repro script, integration test, or clear manual steps.
- Keep tests focused: one behavior per test where possible.
- Name tests by behavior, not implementation details.
Process
- Define the behavior change (what should be true after).
- Write/adjust a test to capture it (make it fail first if possible).
- Implement the minimal change to pass.
- Refactor if needed (keep passing).
- Run the relevant test suite + any linters.
Output requirements
When you change code, include:
- what tests you added/changed
- how to run them
- what they prove