Skill — Testing Standards

When this skill activates

Any task involving writing, running, or improving tests.

Mandatory actions when this skill is active

Before writing tests

1. Identify the exact behavior to verify.
2. Define the failure condition you expect to prevent.

During testing

• Use the AAA pattern with clear separation.
• Keep tests isolated and deterministic.
• Cover both happy and error paths.

After testing

• Run the full test suite.
• Record any new tests in SUMMARY.md with paths.

Coverage targets

Test structure — AAA pattern (non-negotiable)

it('should return 401 when token is expired', async () => {
  // Arrange
  const expiredToken = generateExpiredToken()
  const request = buildRequest({ authorization: `Bearer ${expiredToken}` })

  // Act
  const response = await handler(request)

  // Assert
  expect(response.status).toBe(401)
  expect(response.body.error.code).toBe('TOKEN_EXPIRED')
})

Blank line between Arrange, Act, and Assert sections. Always.

Test naming convention

Pattern: should [expected behaviour] when [condition]

• ✅ should return 404 when user does not exist
• ✅ should hash password before storing in database
• ❌ user test 4
• ❌ test password

Test isolation requirements

• Every test must be able to run independently in any order
• No shared mutable state between tests
• Database state reset between integration tests (use transactions or test containers)
• External services mocked (HTTP, email, SMS, payment providers)
• No sleeps or arbitrary timeouts — use proper async patterns

What to test (and what not to)

Test:

• Business logic and domain rules
• Edge cases: null, empty, boundary values
• Error paths: what happens when dependencies fail
• Security: auth bypass attempts, injection attempts

Do not test:

• Framework internals (trust the framework)
• Simple getters/setters with no logic
• Third-party library behaviour

File placement

• Unit tests: co-located with source (auth.ts → auth.test.ts)
• Integration tests: /tests/integration/
• E2E tests: /tests/e2e/
• Test utilities/fixtures: /tests/utils/

Before marking any task done

Run the full test suite. If any test fails: do not commit. Fix it first.

Self-check before task completion

Before marking a task done when this skill was active:

• [ ] Did I read the full SKILL.md before starting? (Not just the triggers)
• [ ] Did I activate the corresponding persona file?
• [ ] Did I apply every mandatory action in this skill, not just the ones

I remembered off the top of my head?

• [ ] If this skill produced an output file (review, security report, etc.),

has that file been written to the correct path?