test-driven-development · Claude / Claude Code · OpenAI · Codex · Gemini CLI · Grok Build
요구 동작을 테스트로 확인한 뒤 구현과 정리를 진행합니다.
기능을 만들기 전에 기대하는 동작을 테스트로 구체화하는 스킬입니다. 실패하는 테스트를 확인하고 구현으로 통과시킨 뒤 코드를 정리하는 흐름을 사용합니다.
입력과 원하는 결과, 예외 조건을 설명해보세요. 테스트가 기능의 의미를 담도록 정하면 구현을 바꾼 뒤에도 필요한 동작이 유지되는지 확인할 수 있습니다.
“중복된 이메일은 가입되지 않는 기능을 만들어줘. 정상 가입과 중복 입력의 기대 동작을 테스트로 먼저 정의해줘.”
받을 수 있는 결과동작을 검증하는 테스트와 코드
사용 중인 코딩 에이전트에 Superpowers를 설치해야 합니다. 에이전트별 제공 도구는 다를 수 있습니다.
사용하는 환경에 맞는 방법 하나를 선택하세요. Superpowers 전체 패키지를 설치하고 새 세션에서 작업을 요청하면 관련 스킬이 호출됩니다.
Claude Code: /plugin install superpowers@claude-plugins-official Codex 앱: Plugins → Coding → Superpowers 설치 Codex CLI: /plugins → Superpowers → Install Plugin Gemini CLI 터미널: gemini extensions install https://github.com/obra/superpowers
“test-driven-development 스킬을 사용해줘. 입력 자료: 구현할 기능과 기대 동작”처럼 요청하세요. 위의 예시를 내 자료에 맞게 바꿔도 좋아요.
예상 결과는 ‘동작을 검증하는 테스트와 코드’입니다. 필요한 내용이 포함됐는지 확인하세요. 입력 자료의 사실·숫자와 결과를 대조하고, 부족한 부분을 이어서 요청하세요.
제작자 원본 2026-10-04 확인 · 설치 안내 2026-10-04 확인 · 실제 설치·실행 미검증
모델 사용 요금과 연결 앱 요금은 이용 중인 서비스의 정책을 따릅니다.
설치 안내 출처--- name: test-driven-development description: Use when implementing any feature or bugfix, before writing implementation code --- # Test-Driven Development (TDD) ## Overview Write the test first. Watch it fail. Write minimal code to pass. **Core principle:** If you didn't watch the test fail, you don't know if it tests the right thing. **Violating the letter of the rules is violating the spirit of the rules.** ## When to Use **Always:** - New features - Bug fixes - Refactoring - Behavior changes **Exceptions (ask your human partner):** - Throwaway prototypes--- name: test-driven-development description: Use when implementing any feature or bugfix, before writing implementation code --- # Test-Driven Development (TDD) ## Overview Write the test first. Watch it fail. Write minimal code to pass. **Core principle:** If you didn't watch the test fail, you don't know if it tests the right thing. **Violating the letter of the rules is violating the spirit of the rules.** ## When to Use **Always:** - New features - Bug fixes - Refactoring - Behavior changes **Exceptions (ask your human partner):** - Throwaway prototypes - Generated code - Configuration files Thinking "skip TDD just this once"? Stop. That's rationalization. ## The Iron Law ``` NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST ``` Write code before the test? Delete it. Start over. **No exceptions:** - Don't keep it as "reference" - Don't "adapt" it while writing tests - Don't look at it - Delete means delete Implement fresh from tests. Period. ## Red-Green-Refactor ```dot digraph tdd_cycle { rankdir=LR; red [label="RED\nWrite failing test", shape=box, style=filled, fillcolor="#ffcccc"]; verify_red [label="Verify fails\ncorrectly", shape=diamond]; green [label="GREEN\nMinimal code", shape=box, style=filled, fillcolor="#ccffcc"]; verify_green [label="Verify passes\nAll green", shape=diamond]; refactor [label="REFACTOR\nClean up", shape=box, style=filled, fillcolor="#ccccff"]; next [label="Next", shape=ellipse]; red -> verify_red; verify_red -> green [label="yes"]; verify_red -> red [label="wrong\nfailure"]; green -> verify_green; verify_green -> refactor [label="yes"]; verify_green -> green [label="no"]; refactor -> verify_green [label="stay\ngreen"]; verify_green -> next; next -> red; } ``` ### RED - Write Failing Test Write one minimal test showing what should happen. <Good> ```typescript test('retries failed operations 3 times', async () => { let attempts = 0; const operation = () => { attempts++; if (attempts < 3) throw new Error('fail'); return 'success'; }; const result = await retryOperation(operation); expect(result).toBe('success'); expect(attempts).toBe(3); }); ``` Clear name, tests real behavior, one thing </Good> <Bad> ```typescript test('retry works', async () => { const mock = jest.fn() .mockRejectedValueOnce(new Error()) .mockRejectedValueOnce(new Error()) .mockResolvedValueOnce('success'); await retryOperation(mock); expect(mock).toHaveBeenCalledTimes(3); }); ``` Vague name, tests mock not code </Bad> **Requirements:** - One behavior - Clear name - Real code (no mocks unless unavoidable) ### Verify RED - Watch It Fail **MANDATORY. Never skip.** ```bash npm test path/to/test.test.ts ``` Confirm: - Test fails (not errors) - Failure message is expected - Fails because feature missing (not typos) **Test passes?** You're testing existing behavior. Fix test. **Test errors?** Fix error, re-run until it fails correctly. ### GREEN - Minimal Code Write simplest code to pass the test. <Good> ```typescript async function retryOperation<T>(fn: () => Promise<T>): Promise<T> { for (let i = 0; i < 3; i++) { try { return await fn(); } catch (e) { if (i === 2) throw e; } } throw new Error('unreachable'); } ``` Just enough to pass </Good> <Bad> ```typescript async function retryOperation<T>( fn: () => Promise<T>, options?: { maxRetries?: number; backoff?: 'linear' | 'exponential'; onRetry?: (attempt: number) => void; } ): Promise<T> { // YAGNI } ``` Over-engineered </Bad> Don't add features, refactor other code, or "improve" beyond the test. ### Verify GREEN - Watch It Pass **MANDATORY.** ```bash npm test path/to/test.test.ts ``` Confirm: - Test passes - Other tests still pass - Output pristine (no errors, warnings) **Test fails?** Fix code, not test. **Other tests fail?** Fix now. **"Other tests" means the project's suite, not just your file.** A green run of the test you wrote is not a green suite. Before you call the change done, run the project's test command (bare `pytest`, `npm test`, `cargo test` — whatever the repo uses) even when your task named only one test file. A scope statement in your task bounds the deliverable, not your verification. Any failure that run shows — including one you didn't cause — goes in your report by name; a red test you watched scroll past and didn't mention is a report falsified by omission. ### REFACTOR - Clean Up After green only: - Remove duplication - Improve names - Extract helpers Keep tests green. Don't add behavior. ### Repeat Next failing test for next feature. ## Good Tests | Quality | Good | Bad | |---------|------|-----| | **Minimal** | One thing. "and" in name? Split it. | `test('validates email and domain and whitespace')` | | **Clear** | Name describes behavior | `test('test1')` | | **Shows intent** | Demonstrates desired API | Obscures what code should do | When writing or changing any test, read [writing-good-tests.md](writing-good-tests.md) for the rules that keep tests honest: - Name the production change that would make the test fail — before writing it - Assert on real behavior, never on mock behavior - Keep test-only code in test utilities, out of production classes - Understand a dependency's side effects before mocking it ## Common Rationalizations | Excuse | Reality | |--------|---------| | "Too simple to test" | Simple code breaks. Test takes 30 seconds. | | "I'll test after" | Tests written after pass immediately — which proves nothing. They may test the wrong thing, test the implementation instead of the behavior, or miss the edge case you forgot. You never watched it fail, so you never proved it can catch the bug. Test-first forces that failure. | | "Tests after achieve same goals (spirit not ritual)" | Tests-after answer "what does this do?"; tests-first answer "what should this do?" Tests written after are biased by the code you already wrote — you verify the cases you remembered, not the ones you'd have discovered. Coverage without proof the tests work. | | "Already manually tested" | Manual testing is ad-hoc: no record of what you covered, no way to re-run it when the code changes, easy to forget cases under pressure. "Worked when I tried it" ≠ comprehensive. Automated tests run the same way every time. | | "Deleting X hours is wasteful" | Sunk cost fallacy — that time is already spent either way. The real choice: rewrite with TDD (high confidence) vs. keep it and bolt tests on after (low confidence, likely bugs). Keeping code you can't trust is the waste. | | "Keep as reference, write tests first" | You'll adapt it. That's testing after. Delete means delete. | | "Need to explore first" | Fine. Throw away exploration, start with TDD. | | "Test hard = design unclear" | Listen to test. Hard to test = hard to use. | | "TDD will slow me down" | TDD IS the pragmatic path: catches bugs before commit, prevents regressions, lets you refactor without fear. "Pragmatic" shortcuts mean debugging in production — slower, not faster. | | "Manual test faster" | Manual doesn't prove edge cases. You'll re-test every change. | | "Existing code has no tests" | You're improving it. Add tests for existing code. | ## Red Flags - STOP and Start Over - Code before test - Test after implementation - Test passes immediately - Can't explain why test failed - Tests added "later" - Rationalizing "just this once" - "I already manually tested it" - "Tests after achieve the same purpose" - "It's about spirit not ritual" - "Keep as reference" or "adapt existing code" - "Already spent X hours, deleting is wasteful" - "TDD is dogmatic, I'm being pragmatic" - "This is different because..." **All of these mean: Delete code. Start over with TDD.** ## Example: Bug Fix **Bug:** Empty email accepted **RED** ```typescript test('rejects empty email', async () => { const result = await submitForm({ email: '' }); expect(result.error).toBe('Email required'); }); ``` **Verify RED** ```bash $ npm test FAIL: expected 'Email required', got undefined ``` **GREEN** ```typescript function submitForm(data: FormData) { if (!data.email?.trim()) { return { error: 'Email required' }; } // ... } ``` **Verify GREEN** ```bash $ npm test PASS ``` **REFACTOR** Extract validation for multiple fields if needed. ## Verification Checklist Before marking work complete: - [ ] Every new function/method has a test - [ ] Watched each test fail before implementing - [ ] Each test failed for expected reason (feature missing, not typo) - [ ] Wrote minimal code to pass each test - [ ] All tests pass - [ ] Output pristine (no errors, warnings) - [ ] Tests use real code (mocks only if unavoidable) - [ ] Edge cases and errors covered Can't check all boxes? You skipped TDD. Start over. ## When Stuck | Problem | Solution | |---------|----------| | Don't know how to test | Write wished-for API. Write assertion first. Ask your human partner. | | Test too complicated | Design too complicated. Simplify interface. | | Must mock everything | Code too coupled. Use dependency injection. | | Test setup huge | Extract helpers. Still complex? Simplify design. | ## Debugging Integration Bug found? Write failing test reproducing it. Follow TDD cycle. Test proves fix and prevents regression. Never fix bugs without a test. ## Final Rule ``` Production code → test exists and failed first Otherwise → not TDD ``` No exceptions without your human partner's permission.
Original skill: obra/superpowers/skills/test-driven-development/SKILL.md Source: https://github.com/obra/superpowers/blob/8ca22dba9a94f28898bbce59f2537ff4d87c747d/skills/test-driven-development/SKILL.md License: MIT MIT License Copyright (c) 2025 Jesse Vincent Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
SKILL.md 본문입니다. 원문에서 참조하는 스크립트·보조 파일은 원본 패키지에 포함되어 있습니다.