TDD Loop Instruction

기능을 테스트 우선으로 구현하도록 지시

언제 쓰나 · 기능/버그픽스를 견고하게 구현할 때

Implement `{{feature}}` using strict TDD.

1. Write a failing test that pins the desired behavior: {{behavior}}.
2. Run it — confirm it FAILS for the right reason.
3. Write the minimum code to pass.
4. Run — confirm it PASSES.
5. Refactor if needed; tests stay green.

Do not write implementation before the failing test exists. Show test output at each red/green step.