/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](references/config.md) | | test/describe, hooks, fixtures | [test-api.md](references/test-api.md) | | vi.fn, vi.mock, timers, spies | [mocking.md](references/mocking.md) | | expect, snapshots, coverage, filtering | [utilities.md](references/utilities.md) | | Environments, type testing, browser mode | [advanced.md](references/advanced.md) |

Loading Files

**Consider loading these reference files based on your task:**

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