Setting up Vitest with Next.js

Vite and React Testing Library are frequently used together for Unit Testing. This guide will show you how to setup Vitest with Next.js and write your first tests.

Good to know: Since async Server Components are new to the React ecosystem, Vitest currently does not support them. While you can still run unit tests for synchronous Server and Client Components, we recommend using an E2E tests for async components.

Quickstart

You can use create-next-app with the Next.js with-vitest example to quickly get started:

Terminal

npx create-next-app@latest --example with-vitest with-vitest-app

Manual Setup

To manually set up Vitest, install vitest and the following packages as dev dependencies:

Terminal

npm install -D vitest @vitejs/plugin-react jsdom @testing-library/react @testing-library/dom
# or
yarn add -D vitest @vitejs/plugin-react jsdom @testing-library/react @testing-library/dom
# or
pnpm install -D vitest @vitejs/plugin-react jsdom @testing-library/react @testing-library/dom
# or
bun add -D vitest @vitejs/plugin-react jsdom @testing-library/react @testing-library/dom

Create a vitest.config.ts|js file in the root of your project, and add the following options:

vitest.config.ts

import { defineConfig } from 'vitest/config'
import react from '@vitejs/plugin-react'
 
export default defineConfig({
  plugins: [react()],
  test: {
    environment: 'jsdom',
  },
})

For more information on configuring Vitest, please refer to the Vitest Configuration docs.

Then, add a test script to your package.json:

package.json

{
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "next start",
    "test": "vitest"
  }
}

When you run npm run test, Vitest will watch for changes in your project by default.

Creating your first Vitest Unit Test

Check that everything is working by creating a test to check if the <Page /> component successfully renders a heading:

pages/index.tsx

import Link from 'next/link'
 
export default function Page() {
  return (
    <div>
      <h1>Home</h1>
      <Link href="/about">About</Link>
    </div>
  )
}

__tests__/index.test.tsx

import { expect, test } from 'vitest'
import { render, screen } from '@testing-library/react'
import Page from '../pages/index'
 
test('Page', () => {
  render(<Page />)
  expect(screen.getByRole('heading', { level: 1, name: 'Home' })).toBeDefined()
})

Running your tests

Then, run the following command to run your tests:

Terminal

npm run test
# or
yarn test
# or
pnpm test
# or
bun test

Additional Resources

You may find these resources helpful: