Test Quality Analysis

This analyzes your test suite for common problems like overmocking, flaky tests, and weak assertions. It checks whether you're testing behavior instead of implementation details, flags tests with too many mocks (more than 3-4 is a smell), and helps you spot fragile selectors or race conditions. Works with Vitest, pytest, and Playwright. The coverage analysis goes beyond just percentage to look at whether critical paths and error cases are actually tested. Use it during code review or when tests keep breaking for no clear reason. The FIRST principles checklist and anti-pattern examples are genuinely helpful for spotting tests that look fine but won't catch real bugs.

skills.sh installs: 469
GitHub stars: 248
last updated: Aug 21, 2026

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Install

$ npx -y skills add secondsky/claude-skills --skill test-quality-analysis --agent claude-code

Installs into .claude/skills of the current project.

Files

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.

// ❌ 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).