vitest's Introduction

Vitest

A blazing fast unit test framework powered by Vite.

Get involved!

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

Vitest requires Vite v2.7 and Node v14

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

Documentation

Read the documentation.

Features

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

Examples

Projects using Vitest

Credits

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!