npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2019 – Ryan Hefner

@testing-library/react

v9.1.4

Published

Simple and complete React DOM testing utilities that encourage good testing practices.

Downloads

1,601,102

Readme

React Testing Library

goat

Simple and complete React DOM testing utilities that encourage good testing practices.


Read The Docs | Edit the docs



Build Status Code Coverage version downloads MIT License

All Contributors PRs Welcome Code of Conduct Join the community on Spectrum

Watch on GitHub Star on GitHub Tweet

Table of Contents

The problem

You want to write maintainable tests for your React components. As a part of this goal, you want your tests to avoid including implementation details of your components and rather focus on making your tests give you the confidence for which they are intended. As part of this, you want your testbase to be maintainable in the long run so refactors of your components (changes to implementation but not functionality) don't break your tests and slow you and your team down.

This solution

The React Testing Library is a very lightweight solution for testing React components. It provides light utility functions on top of react-dom and react-dom/test-utils, in a way that encourages better testing practices. Its primary guiding principle is:

The more your tests resemble the way your software is used, the more confidence they can give you.

Installation

This module is distributed via npm which is bundled with node and should be installed as one of your project's devDependencies:

npm install --save-dev @testing-library/react

This library has peerDependencies listings for react and react-dom.

You may also be interested in installing @testing-library/jest-dom so you can use the custom jest matchers.

Docs

Suppressing unnecessary warnings on React DOM 16.8

There is a known compatibility issue with React DOM 16.8 where you will see the following warning:

Warning: An update to ComponentName inside a test was not wrapped in act(...).

If you cannot upgrade to React DOM 16.9, you may suppress the warnings by adding the following snippet to your test configuration (learn more):

// this is just a little hack to silence a warning that we'll get until we
// upgrade to 16.9: https://github.com/facebook/react/pull/14853
const originalError = console.error
beforeAll(() => {
  console.error = (...args) => {
    if (/Warning.*not wrapped in act/.test(args[0])) {
      return
    }
    originalError.call(console, ...args)
  }
})

afterAll(() => {
  console.error = originalError
})

Examples

Basic Example

// hidden-message.js
import React from 'react'

// NOTE: React Testing Library works with React Hooks _and_ classes just as well
// and your tests will be the same however you write your components.
function HiddenMessage({children}) {
  const [showMessage, setShowMessage] = React.useState(false)
  return (
    <div>
      <label htmlFor="toggle">Show Message</label>
      <input
        id="toggle"
        type="checkbox"
        onChange={e => setShowMessage(e.target.checked)}
        checked={showMessage}
      />
      {showMessage ? children : null}
    </div>
  )
}

export default HiddenMessage

// __tests__/hidden-message.js
// these imports are something you'd normally configure Jest to import for you
// automatically. Learn more in the setup docs: https://testing-library.com/docs/react-testing-library/setup#cleanup
import '@testing-library/jest-dom/extend-expect'
// NOTE: jest-dom adds handy assertions to Jest and is recommended, but not required

import React from 'react'
import {render, fireEvent} from '@testing-library/react'
import HiddenMessage from '../hidden-message'

test('shows the children when the checkbox is checked', () => {
  const testMessage = 'Test Message'
  const {queryByText, getByLabelText, getByText} = render(
    <HiddenMessage>{testMessage}</HiddenMessage>,
  )

  // query* functions will return the element or null if it cannot be found
  // get* functions will return the element or throw an error if it cannot be found
  expect(queryByText(testMessage)).toBeNull()

  // the queries can accept a regex to make your selectors more resilient to content tweaks and changes.
  fireEvent.click(getByLabelText(/show/i))

  // .toBeInTheDocument() is an assertion that comes from jest-dom
  // otherwise you could use .toBeDefined()
  expect(getByText(testMessage)).toBeInTheDocument()
})

Complex Example

// login.js
import React from 'react'

function Login() {
  const [state, setState] = React.useReducer((s, a) => ({...s, ...a}), {
    resolved: false,
    loading: false,
    error: null,
  })

  function handleSubmit(event) {
    event.preventDefault()
    const {usernameInput, passwordInput} = event.target.elements

    setState({loading: true, resolved: false, error: null})

    window
      .fetch('/api/login', {
        method: 'POST',
        headers: {'Content-Type': 'application/json'},
        body: JSON.stringify({
          username: usernameInput.value,
          password: passwordInput.value,
        }),
      })
      .then(r => r.json())
      .then(
        user => {
          setState({loading: false, resolved: true, error: null})
          window.localStorage.setItem('token', user.token)
        },
        error => {
          setState({loading: false, resolved: false, error: error.message})
        },
      )
  }

  return (
    <div>
      <form onSubmit={handleSubmit}>
        <div>
          <label htmlFor="usernameInput">Username</label>
          <input id="usernameInput" />
        </div>
        <div>
          <label htmlFor="passwordInput">Password</label>
          <input id="passwordInput" type="password" />
        </div>
        <button type="submit">Submit{state.loading ? '...' : null}</button>
      </form>
      {state.error ? <div role="alert">{state.error.message}</div> : null}
      {state.resolved ? (
        <div role="alert">Congrats! You're signed in!</div>
      ) : null}
    </div>
  )
}

export default Login

// __tests__/login.js
// again, these first two imports are something you'd normally handle in
// your testing framework configuration rather than importing them in every file.
import '@testing-library/jest-dom/extend-expect'
import React from 'react'
import {render, fireEvent} from '@testing-library/react'
import Login from '../login'

test('allows the user to login successfully', async () => {
  // mock out window.fetch for the test
  const fakeUserResponse = {token: 'fake_user_token'}
  jest.spyOn(window, 'fetch').mockImplementationOnce(() => {
    return Promise.resolve({
      json: () => Promise.resolve(fakeUserResponse),
    })
  })

  const {getByLabelText, getByText, findByRole} = render(<Login />)

  // fill out the form
  fireEvent.change(getByLabelText(/username/i), {target: {value: 'chuck'}})
  fireEvent.change(getByLabelText(/password/i), {target: {value: 'norris'}})

  fireEvent.click(getByText(/submit/i))

  // just like a manual tester, we'll instruct our test to wait for the alert
  // to show up before continuing with our assertions.
  const alert = await findByRole('alert')

  // .toHaveTextContent() comes from jest-dom's assertions
  // otherwise you could use expect(alert.textContent).toMatch(/congrats/i)
  // but jest-dom will give you better error messages which is why it's recommended
  expect(alert).toHaveTextContent(/congrats/i)
  expect(window.localStorage.getItem('token')).toEqual(fakeUserResponse.token)
})

More Examples

We're in the process of moving examples to the docs site

You'll find runnable examples of testing with different libraries in the react-testing-library-examples codesandbox. Some included are:

You can also find React Testing Library examples at react-testing-examples.com.

Hooks

If you are interested in testing a custom hook, check out React Hooks Testing Library.

NOTE it is not recommended to test single-use custom hooks in isolation from the components where it's being used. It's better to test the component that's using the hook rather than the hook itself. The React Hooks Testing Library is intended to be used for reusable hooks/libraries.

Guiding Principles

The more your tests resemble the way your software is used, the more confidence they can give you.

We try to only expose methods and utilities that encourage you to write tests that closely resemble how your react components are used.

Utilities are included in this project based on the following guiding principles:

  1. If it relates to rendering components, it deals with DOM nodes rather than component instances, nor should it encourage dealing with component instances.
  2. It should be generally useful for testing individual React components or full React applications. While this library is focused on react-dom, utilities could be included even if they don't directly relate to react-dom.
  3. Utility implementations and APIs should be simple and flexible.

At the end of the day, what we want is for this library to be pretty light-weight, simple, and understandable.

Docs

Read The Docs | Edit the docs

Issues

Looking to contribute? Look for the Good First Issue label.

🐛 Bugs

Please file an issue for bugs, missing documentation, or unexpected behavior.

See Bugs

💡 Feature Requests

Please file an issue to suggest new features. Vote on feature requests by adding a 👍. This helps maintainers prioritize what to work on.

See Feature Requests

❓ Questions

For questions related to using the library, please visit a support community instead of filing an issue on GitHub.

Contributors

Thanks goes to these people (emoji key):

Kent C. Dodds
Kent C. Dodds

💻 📖 🚇 ⚠️
Ryan Castner
Ryan Castner

📖
Daniel Sandiego
Daniel Sandiego

💻
Paweł Mikołajczyk
Paweł Mikołajczyk

💻
Alejandro Ñáñez Ortiz
Alejandro Ñáñez Ortiz

📖
Matt Parrish
Matt Parrish

🐛 💻 📖 ⚠️
Justin Hall
Justin Hall

📦
Anto Aravinth
Anto Aravinth

💻 ⚠️ 📖
Jonah Moses
Jonah Moses

📖
Łukasz Gandecki
Łukasz Gandecki

💻 ⚠️ 📖
Ivan Babak
Ivan Babak

🐛 🤔
Jesse Day
Jesse Day

💻
Ernesto García
Ernesto García

💬 💻 📖
Josef Maxx Blake
Josef Maxx Blake

💻 📖 ⚠️
Michal Baranowski
Michal Baranowski

📝
Arthur Puthin
Arthur Puthin

📖
Thomas Chia
Thomas Chia

💻 📖
Thiago Galvani
Thiago Galvani

📖
Christian
Christian

⚠️
Alex Krolick
Alex Krolick

💬 📖 💡 🤔
Johann Hubert Sonntagbauer
Johann Hubert Sonntagbauer

💻 📖 ⚠️
Maddi Joyce
Maddi Joyce

💻
Ryan Vice
Ryan Vice

📖
Ian Wilson
Ian Wilson

📝
Daniel
Daniel

🐛 💻
Giorgio Polvara
Giorgio Polvara

🐛 🤔
John Gozde
John Gozde

💻
Sam Horton
Sam Horton

📖 💡 🤔
Richard Kotze (mobile)
Richard Kotze (mobile)

📖
Brahian E. Soto Mercedes
Brahian E. Soto Mercedes

📖
Benoit de La Forest
Benoit de La Forest

📖
Salah
Salah

💻 ⚠️
Adam Gordon
Adam Gordon

🐛 💻
Matija Marohnić
Matija Marohnić

📖
Justice Mba
Justice Mba

📖
Mark Pollmann
Mark Pollmann

📖
Ehtesham Kafeel
Ehtesham Kafeel

💻 📖
Julio Pavón
Julio Pavón

💻
Duncan L
Duncan L

📖 💡
Tiago Almeida
Tiago Almeida

📖
Robert Smith
Robert Smith

🐛
Zach Green
Zach Green

📖
dadamssg
dadamssg

📖
Yazan Aabed
Yazan Aabed

📝
Tim
Tim

🐛 💻 📖 ⚠️
Divyanshu Maithani
Divyanshu Maithani

📹
Deepak Grover
Deepak Grover

📹
Eyal Cohen
Eyal Cohen

📖
Peter Makowski
Peter Makowski

📖
Michiel Nuyts
Michiel Nuyts

📖
Joe Ng'ethe
Joe Ng'ethe

💻 📖
Kate
Kate

📖
Sean
Sean

📖
James Long
James Long

🤔 📦
Herb Hagely
Herb Hagely

💡
Alex Wendte
Alex Wendte

💡
Monica Powell
Monica Powell

📖
Vitaly Sivkov
Vitaly Sivkov

💻
Weyert de Boer
Weyert de Boer

🤔 👀
EstebanMarin
EstebanMarin

📖
Victor Martins
Victor Martins

📖
Royston Shufflebotham
Royston Shufflebotham

🐛 📖 💡
chrbala
chrbala

💻
Donavon West
Donavon West

💻 📖 🤔 ⚠️
Richard Maisano
Richard Maisano

💻
Marco Biedermann
Marco Biedermann

💻 🚧 ⚠️
Alex Zherdev
Alex Zherdev

🐛 💻
André Matulionis dos Santos
André Matulionis dos Santos

💻 💡 ⚠️
Daniel K.
Daniel K.

🐛 💻 🤔 ⚠️ 👀
mohamedmagdy17593
mohamedmagdy17593

💻
Loren ☺️
Loren ☺️

📖
MarkFalconbridge
MarkFalconbridge

🐛 💻
Vinicius
Vinicius

📖 💡
Peter Schyma
Peter Schyma

💻
Ian Schmitz
Ian Schmitz

📖
Joel Marcotte
Joel Marcotte

🐛 ⚠️ 💻
Alejandro Dustet
Alejandro Dustet

🐛
Brandon Carroll
Brandon Carroll

📖
Lucas Machado
Lucas Machado

📖
Pascal Duez
Pascal Duez

📦
Minh Nguyen
Minh Nguyen

💻
LiaoJimmy
LiaoJimmy

📖
Sunil Pai
Sunil Pai

💻 ⚠️
Dan Abramov
Dan Abramov

👀
Christian Murphy
Christian Murphy

🚇
Ivakhnenko Dmitry
Ivakhnenko Dmitry

💻
James George
James George

📖
João Fernandes
João Fernandes

📖
Alejandro Perea
Alejandro Perea

👀
Nick McCurdy
Nick McCurdy

👀
Sebastian Silbermann
Sebastian Silbermann

👀
Adrià Fontcuberta
Adrià Fontcuberta

👀 📖
John Reilly
John Reilly

👀
Michaël De Boey
Michaël De Boey

👀
Tim Yates
Tim Yates

👀
Brian Donovan
Brian Donovan

💻
Noam Gabriel Jacobson
Noam Gabriel Jacobson

📖
Ronald van der Kooij
Ronald van der Kooij

⚠️ 💻
Aayush Rajvanshi
Aayush Rajvanshi

📖
Ely Alamillo
Ely Alamillo

💻 ⚠️

This project follows the all-contributors specification. Contributions of any kind welcome!

LICENSE

MIT