vitest

---

name: vitest description: Use when writing unit/integration tests for Vite projects - configure vitest.config.ts, write test suites with describe/it, create mock implementations with vi.fn and vi.mock, set up code coverage thresholds, and run tests in parallel license: MIT

Vitest

Vite-native testing framework with Jest-compatible API.

When to Use

• Writing unit/integration tests for Vite projects
• Testing Vue/React/Svelte components
• Mocking modules, timers, or dates
• Running concurrent/parallel tests
• Type testing with TypeScript

Quick Start

npm i -D vitest

// vitest.config.ts
import { defineConfig } from 'vitest/config'

export default defineConfig({
  test: {
    globals: true,
    environment: 'node',  // or 'jsdom' for DOM tests
  },
})

// example.test.ts
import { describe, expect, it, vi } from 'vitest'

describe('math', () => {
  it('adds numbers', () => {
    expect(1 + 1).toBe(2)
  })
})

Reference Files

Task	File
Configuration, CLI, projects	config.md
test/describe, hooks, fixtures	test-api.md
vi.fn, vi.mock, timers, spies	mocking.md
expect, snapshots, coverage, filtering	utilities.md
Environments, type testing, browser mode	advanced.md

Loading Files

Consider loading these reference files based on your task:

• references/config.md - if setting up vitest.config.ts, CLI, or workspace projects
• references/test-api.md - if writing test/describe blocks, using hooks, or test fixtures
• references/mocking.md - if mocking modules, timers, dates, or using spies
• references/utilities.md - if writing assertions, snapshots, or configuring coverage
• references/advanced.md - if configuring test environments, type testing, or browser mode

DO NOT load all files at once. Load only what's relevant to your current task.

Cross-Skill References

• Vue component testing → Use vue skill for component patterns
• Library testing → Use ts-library skill for library patterns
• Vite configuration → Use vite skill for shared config