사용 방법
- 설치 명령을 복사하고 자신의 에이전트 환경에 설치하기 전에 소스 패키지를 확인하세요.
- 필요한 도구, 인증 정보, 지원 환경은 원본 문서에서 확인하세요.
- 입력과 원하는 산출물을 설명하고 출처와 결과를 대조하세요.
npx skills add https://github.com/secondsky/claude-skills --skill test-quality-analysis시작 전 확인
- 설치에는 모델 구독, API 한도, 파일 접근 권한이 포함되지 않습니다.
- 별점 수와 설치 수는 활동 지표이며 독립적인 품질·보안 검증이 아닙니다.
원본 Skill 문서
원본 저장소의 제목, 예시, 코드, 표, 링크, 이미지를 유지해 표시합니다.
Test Quality Analysis
Expert knowledge for analyzing and improving test quality - detecting test smells, overmocking, insufficient coverage, and testing anti-patterns.
Core Dimensions
- Correctness: Tests verify the right behavior
- Reliability: Tests are deterministic, not flaky
- Maintainability: Tests are easy to understand
- Performance: Tests run quickly
- Coverage: Tests cover critical code paths
- Isolation: Tests don't depend on external state
Test Smells
Overmocking
Problem: Mocking too many dependencies makes tests fragile.
typescript
// ❌ BAD: Overmocked
test('calculate total', () => {
const mockAdd = vi.fn(() => 10)
const mockMultiply = vi.fn(() => 20)
// Testing implementation, not behavior
})
// ✅ GOOD: Mock only external dependencies
test('calculate order total', () => {
const mockPricingAPI = vi.fn(() => ({ tax: 0.1 }))
const total = calculateTotal(order, mockPricingAPI)
expect(total).toBe(38)
})Detection: More than 3-4 mocks, mocking pure functions, complex mock setup.
Fix: Mock only I/O boundaries (APIs, databases, filesystem).
Fragile Tests
Problem: Tests break with unrelated code changes.
typescript
// ❌ BAD: Tests implementation details
await page.locator('.form-container > div:nth-child(2) > button').click()
// ✅ GOOD: Semantic selector
await page.getByRole('button', { name: 'Submit' }).click()Flaky Tests
Problem: Tests pass or fail non-deterministically.
typescript
// ❌ BAD: Race condition
test('loads data', async () => {
fetchData()
await new Promise(resolve => setTimeout(resolve, 1000))
expect(data).toBeDefined()
})
// ✅ GOOD: Proper async handling
test('loads data', async () => {
const data = await fetchData()
expect(data).toBeDefined()
})Poor Assertions
typescript
// ❌ BAD: Weak assertion
test('returns users', async () => {
const users = await getUsers()
expect(users).toBeDefined() // Too vague!
})
// ✅ GOOD: Strong, specific assertions
test('creates user with correct attributes', async () => {
const user = await createUser({ name: 'John' })
expect(user).toMatchObject({
id: expect.any(Number),
name: 'John',
})
})Analysis Tools
bash
# Vitest coverage (prefer bun)
bun test --coverage
open coverage/index.html
# Check thresholds
bun test --coverage --coverage.thresholds.lines=80
# pytest-cov (Python)
uv run pytest --cov --cov-report=html
open htmlcov/index.htmlBest Practices Checklist
Unit Test Quality (FIRST)
- [ ] Fast: Tests run in milliseconds
- [ ] Isolated: No dependencies between tests
- [ ] Repeatable: Same results every time
- [ ] Self-validating: Clear pass/fail
- [ ] Timely: Written alongside code
Mock Guidelines
- [ ] Mock only external dependencies
- [ ] Don't mock business logic or pure functions
- [ ] Use real implementations when possible
- [ ] Limit to 3-4 mocks per test maximum
Coverage Goals
- [ ] 80%+ line coverage for business logic
- [ ] 100% for critical paths (auth, payment)
- [ ] All error paths tested
- [ ] Boundary conditions tested
Test Structure (AAA Pattern)
typescript
test('user registration', async () => {
// Arrange
const userData = { email: 'user@example.com' }
// Act
const user = await registerUser(userData)
// Assert
expect(user.email).toBe('user@example.com')
})Code Review Checklist
- [ ] Tests verify behavior, not implementation
- [ ] Assertions are specific and meaningful
- [ ] No flaky tests (timing, ordering issues)
- [ ] Proper async/await usage
- [ ] Test names clearly describe behavior
- [ ] Minimal code duplication
- [ ] Critical paths have tests
- [ ] Both happy path and error cases covered
Common Anti-Patterns
Testing Implementation Details
typescript
// ❌ BAD
const spy = vi.spyOn(Math, 'sqrt')
calculateDistance()
expect(spy).toHaveBeenCalled() // Testing how, not what
// ✅ GOOD
const distance = calculateDistance({ x: 0, y: 0 }, { x: 3, y: 4 })
expect(distance).toBe(5) // Testing outputMocking Too Much
typescript
// ❌ BAD
const mockAdd = vi.fn((a, b) => a + b)
// ✅ GOOD: Use real implementations
import { add } from './utils'
// Only mock external services
const mockPaymentGateway = vi.fn()See Also
vitest-testing- TypeScript/JavaScript testingplaywright-testing- E2E testingmutation-testing- Validate test effectiveness
