SKILL.md
Test-Driven Development
Use this workflow when the user wants new behavior developed under TDD discipline, or when a risky behavior change benefits from a failing test before implementation.
Workflow
- Specify the behavior in one or two concrete sentences and identify the test framework.
- Red: write one focused test that captures the requested behavior. Prefer existing test patterns and fixtures. Run it and confirm it fails for the expected reason.
- Green: implement the smallest code change that makes the failing test pass. Avoid speculative options, broad rewrites, or unrelated cleanup.
- Run the focused test. If it still fails, fix the implementation rather than weakening the test unless the test contradicts the stated behavior.
- Refactor: clean only the code introduced or directly touched by the change. Preserve public APIs, return values, side effects, and data formats.
- Run the focused test again, then related tests for the touched area.
- Repeat the loop for each distinct behavior instead of writing a broad test batch up front.
When subagents are available, keep phases isolated: pass the behavior only to a test-writing subagent, pass the failing test only to an implementation subagent, and pass the green code only to a refactoring subagent.
Final Report
Include:
- behavior implemented
- red test added or updated
- implementation files changed
- refactor changes applied
- tests run and result
- remaining risks or follow-up tests