test-quality-analysis

# 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-determinist...