Repository: vitest-dev/vitest

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CLAUDE.md Copy Chapter

@AGENTS.md

README.md Copy Chapter

<p align="center">
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<a href="https://vitest.dev" target="_blank" rel="noopener noreferrer">
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<source media="(prefers-color-scheme: dark)" srcset="https://vitest.dev/vitest-light.svg">
<source media="(prefers-color-scheme: light)" srcset="https://vitest.dev/vitest-dark.svg">
<img alt="Vitest logo" src="https://vitest.dev/vitest-dark.svg" height="60">
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<h1 align="center">
Vitest
</h1>
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Next generation testing framework powered by Vite.
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<p align="center">
<a href="https://npmx.dev/package/vitest"><img src="https://img.shields.io/npm/v/vitest?color=729B1B&label=" alt="current vitest version badge"></a>
<p>

<p align="center">
<a href="https://chat.vitest.dev"><b>Get involved!</b></a>
</p>
<p align="center">
<a href="https://vitest.dev">Documentation</a> | <a href="https://vitest.dev/guide/">Getting Started</a> | <a href="https://vitest.dev/guide/#examples">Examples</a> | <a href="https://vitest.dev/guide/why">Why Vitest?</a>
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<a href="https://cn.vitest.dev">中文文档</a>
</p>

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Features Copy Chapter

- 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 v8 or istanbul.
- Jest-compatible mocking, stubbing, and spies.
- JSDOM and happy-dom for DOM and browser API mocking
- Browser Mode for running component tests in the browser
- Components testing (Vue, React, Svelte, Lit, Marko)
- Benchmarking support with Tinybench
- Projects support
- expect-type for type-level testing
- ESM first, top level await
- Out-of-box TypeScript / JSX support
- Filtering, timeouts, concurrent for suite and tests
- Sharding support
- Reporting Uncaught Errors
- Run your tests in the browser natively

Vitest requires Vite >=v6.0.0 and Node >=v20.0.0

import { assert, describe, expect, it } 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

Sponsors Copy Chapter

<p align="center">
<a href="https://cdn.jsdelivr.net/gh/sheremet-va/static/vitest/sponsors.svg">
<img src='https://cdn.jsdelivr.net/gh/sheremet-va/static/vitest/sponsors.svg' alt="vitest's sponsors"/>
</a>
</p>

Vladimir Sponsors Copy Section

<p align="center">
<a href="https://cdn.jsdelivr.net/gh/sheremet-va/static/sponsors.svg">
<img src='https://cdn.jsdelivr.net/gh/sheremet-va/static/sponsors.svg' alt="vladimir's sponsors"/>
</a>
</p>

Anthony Fu Sponsors Copy Section

<p align="center">
<a href="https://cdn.jsdelivr.net/gh/antfu/static/sponsors.svg">
<img src='https://cdn.jsdelivr.net/gh/antfu/static/sponsors.svg' alt="anthony's sponsors"/>
</a>
</p>

Patak Sponsors Copy Section

<p align="center">
<a href="https://cdn.jsdelivr.net/gh/patak-dev/static/sponsors.svg">
<img src='https://cdn.jsdelivr.net/gh/patak-dev/static/sponsors.svg' alt="patak's sponsors"/>
</a>
</p>

Credits Copy Chapter

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!

Contribution Copy Chapter

See Contributing Guide.

License Copy Chapter

MIT License © 2021-Present VoidZero Inc. and Vitest contributors