secondsky/claude-skills

test-quality-analysis

Detect test smells, overmocking, flaky tests, and coverage issues.

查看源码

使用方法

  1. 复制安装命令,在自己的智能体环境安装前先检查源码包。
  2. 从原始文档核对所需工具、凭据和支持的宿主。
  3. 说明输入材料与期望交付物,并对照来源检查输出。
npx skills add https://github.com/secondsky/claude-skills --skill test-quality-analysis

开始前需了解

  • 安装不包含模型订阅、API 额度或访问文件的权限。
  • 仓库星数和安装量反映活跃情况,不等于独立质量或安全测试。
仓库原始内容

按源仓库内容呈现,保留标题、案例、代码、表格、链接以及原文引用的演示图片。

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.html

Best 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 output

Mocking 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 testing
  • playwright-testing - E2E testing
  • mutation-testing - Validate test effectiveness

按任务相关推荐

来自同一仓库

更多 Skills

全部 Skills