Test-Driven Development
The Cycle
RED → GREEN → REFACTOR
Never skip RED. Never write code before a failing test exists.
Steps
- Write the failing test — specific, tests one behavior
- Run it and confirm it fails — with the right error message
- Write minimal code to make it pass — no more than needed
- Run it and confirm it passes
- Refactor if needed — tests still pass after refactor
- Commit — small, frequent commits
Anti-Patterns to Avoid
- Writing implementation before tests
- Tests that pass without any implementation (false green)
- Testing implementation details instead of behavior
- One giant test instead of small focused tests
- Skipping the refactor step
Verification Command
Always show the exact command to run tests and expected output at each RED/GREEN step.
Source: hashgraph-online/awesome-codex-plugins → plugins/yimwoo/hotl-plugin/skills/tdd/SKILL.md