A blazing fast unit test framework powered by Vite.

⚠️ DISCLAIMER: Vitest is still in development and not stable yet. It's not recommended to use it in production.

Vitest requires Vite >=v2.7.10 and Node >=v14

Follow the Getting Started Guide or learn why we are building a new test runner.

Read the documentation.

Examples | Projects using Vitest

• Vite's config, transformers, resolvers, and plugins. Use the same setup from your app!
• Jest Snapshot
• Chai built-in for assertions, with Jest expect compatible APIs.
• Smart & instant watch mode, like HMR for tests!
• Native code coverage via c8
• Tinyspy built-in for mocking, stubbing, and spies.
• JSDOM and happy-dom for DOM and browser API mocking
• Components testing (Vue, React, Lit, Vitesse)
• Workers multi-threading via tinypool (a lightweight fork of Piscina)
• ESM first, top level await
• Out-of-box TypeScript / JSX support
• Filtering, timeouts, concurrent for suite and tests

import { it, describe, expect, assert } from 'vitest'

describe('suite name', () => {
  it('foo', () => {
    expect(1 + 1).toEqual(2)
    expect(true).to.be.true
  })

  it('bar', () => {
    assert.equal(Math.sqrt(4), 2)
  })

  it('snapshot', () => {
    expect({ foo: 'bar' }).toMatchSnapshot()
  })
})

$ npx vitest

Thanks to:

• The Jest team and community for creating a delightful testing API
• @lukeed for the work on uvu where we are inspired a lot from.
• @pi0 for the idea and implementation of using Vite to transform and bundle the server code.
• The Vite team for brainstorming the initial idea.
• @patak-dev for the awesome package name!

MIT License © 2021-Present Anthony Fu, Matias Capeletto