unit-test

name	unit-test
description	Write and maintain unit tests with Vitest. Test titles MUST be English `it('should ...')` strings. Use when adding or updating unit tests, improving test coverage, or handling unavoidable coverage gaps with documented ignore comments.

Unit Test

Rules

1. Unit tests use Vitest.
2. Coverage target is 100%.
3. If coverage cannot be achieved in a realistic way, add an ignore comment and keep total coverage at 100%.
4. Every ignore comment must include a clear reason.
5. Always import test APIs (e.g., vi, it, expect, describe, beforeEach, afterEach) directly from vitest; do not rely on globals. Do not use Vitest’s test(...) alias — use it(...) only for individual test cases.

Test titles (it descriptions)

Non-negotiable: Every it(...) title is a single English string that starts with the word should (lowercase should right after the opening quote). Use it('should ...', () => { ... }) or it('should ...', async () => { ... }).

• Do: it('should return false when the input is empty', ...)
• Do: it('should run the registered cleanup at most once even if the cleanup throws', ...)
• Don't: it('returns false when ...') — missing should
• Don't: it('Runs cleanup...') — title case sentence without should
• Don't: it('clears ref when...') — verb-first fragment without should

Before you finish editing a spec file, scan every it( and confirm the first word inside the string is should. Do not introduce test( anywhere in the file.

Other strings (describe blocks, comments) may be English or match surrounding file style; the it title rule is fixed.

Mocking

• .cursor/skills/unit-test/mocking/SKILL.md