test-quality

name	test-quality
description	[pr-review-focus-area: Tests] Assess test quality by detecting anti-patterns and verifying tests exercise real behavior.
user-invocable	true
disable-model-invocation	true
allowed-tools	["Read","Grep","Glob"]

Test Quality Review

Assess the quality of existing tests by detecting anti-patterns and verifying tests exercise real behavior.

Invocation

/test-quality — review quality of test files for changed source files, or all tests if specified.

Anti-Pattern Detection

Examples shown in React/Jest syntax. Adapt patterns to your framework's equivalent APIs.

Prop-Echo Tests

Tests that just verify a component renders what you pass in.

// BAD: just echoing the prop back
render(<Title text="Hello" />)
expect(screen.getByText("Hello")).toBeInTheDocument()

Flag when the only assertion is checking that a passed prop appears in output.

Mock-In / Mock-Out Tests

Tests where you mock the input and assert the mock was called, testing nothing real.

// BAD: mock in, mock out
const mockFn = jest.fn()
doThing(mockFn)
expect(mockFn).toHaveBeenCalled()

Flag when mocks are both the input and the assertion target.

Render-Only Tests

Tests that just check a component renders without crashing, with no meaningful assertions.

// BAD: render-only
it('renders', () => {
  render(<Dashboard />)
})

Flag tests with zero assertions or only expect(container).toBeDefined().

Shallow Assertions

Tests that use weak assertions that would pass for almost any value.

• toBeDefined() on complex objects
• toBeTruthy() on non-boolean values
• toHaveLength() without checking content
• toContain() with trivial substrings

Over-Mocking

Tests that mock so many dependencies that they test nothing real.

• Flag tests with more than 5 mocks.
• Flag tests where all imported modules are mocked.
• Flag tests that mock the module under test.

Test Duplication

• Flag tests with identical or near-identical setup and assertions.
• Suggest parameterized tests or shared fixtures.

Positive Quality Indicators

Tests should exercise:

• User interactions: Click, type, submit, navigate.
• State changes: Before/after comparisons, UI updates after actions.
• Error handling: Invalid inputs, API failures, boundary conditions.
• Integration: Components working with real (or minimally mocked) dependencies.
• Accessibility: ARIA roles, keyboard navigation, screen reader text.

Report Format

## Test Quality Report

### Anti-Patterns Found
- [WARN] src/components/__tests__/Button.test.tsx — prop-echo test (3 tests just check rendered text matches props)
- [WARN] src/lib/__tests__/api.test.ts — mock-in/mock-out (2 tests only verify mock calls)
- [WARN] src/pages/__tests__/Home.test.tsx — render-only (1 test with no assertions)

### Quality Scores
| Test File                  | Tests | Anti-Patterns | Functional | Score  |
| -------------------------- | ----- | ------------- | ---------- | ------ |
| Button.test.tsx            | 5     | 3             | 2          | 40%    |
| api.test.ts                | 8     | 2             | 6          | 75%    |
| Home.test.tsx              | 3     | 1             | 2          | 67%    |

### Overall: 61% functional (10/16 tests exercise real behavior)

### Recommendations
1. Button.test.tsx: Add interaction tests (click handlers, disabled state, loading state)
2. api.test.ts: Replace mock-only tests with integration tests using MSW or similar
3. Home.test.tsx: Add assertions for page content, navigation, and error state