react-testing-library

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

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The problem
This solution
Example
Installation
Examples
Hooks
Other Solutions
Guiding Principles
Contributors
Docs
Issues
LICENSE

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.

Example

// __tests__/fetch.js
import React from 'react'
import {render, fireEvent, cleanup, waitForElement} from 'react-testing-library'
// this adds custom jest matchers from jest-dom
import 'jest-dom/extend-expect'

// the mock lives in a __mocks__ directory
// to know more about manual mocks, access: https://jestjs.io/docs/en/manual-mocks
import axiosMock from 'axios'
import Fetch from '../fetch' // see the tests for a full implementation

// automatically unmount and cleanup DOM after the test is finished.
afterEach(cleanup)

test('Fetch makes an API call and displays the greeting when load-greeting is clicked', async () => {
  // Arrange
  axiosMock.get.mockResolvedValueOnce({data: {greeting: 'hello there'}})
  const url = '/greeting'
  const {getByText, getByTestId, container, asFragment} = render(
    <Fetch url={url} />,
  )

  // Act
  fireEvent.click(getByText(/load greeting/i))

  // Let's wait until our mocked `get` request promise resolves and
  // the component calls setState and re-renders.
  // getByTestId throws an error if it cannot find an element with the given ID
  // and waitForElement will wait until the callback doesn't throw an error
  const greetingTextNode = await waitForElement(() =>
    getByTestId('greeting-text'),
  )

  // Assert
  expect(axiosMock.get).toHaveBeenCalledTimes(1)
  expect(axiosMock.get).toHaveBeenCalledWith(url)
  expect(getByTestId('greeting-text')).toHaveTextContent('hello there')
  expect(getByTestId('ok-button')).toHaveAttribute('disabled')
  // snapshots work great with regular DOM nodes!
  expect(container.firstChild).toMatchSnapshot()
  // you can also get a `DocumentFragment`, which is useful if you want to compare nodes across renders
  expect(asFragment()).toMatchSnapshot()
})

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 react-testing-library

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

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

Docs

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 examples directory. 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

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:

If it relates to rendering components, it deals with DOM nodes rather than component instances, nor should it encourage dealing with component instances.
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.
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.

Contributors

Thanks goes to these people (emoji key):

_{Kent C. Dodds} 💻 📖 🚇 ⚠️	_{Ryan Castner} 📖	_{Daniel Sandiego} 💻	_{Paweł Mikołajczyk} 💻	_{Alejandro Ñáñez Ortiz} 📖	_{Matt Parrish} 🐛 💻 📖 ⚠️	_{Justin Hall} 📦
_{Anto Aravinth} 💻 ⚠️ 📖	_{Jonah Moses} 📖	_{Łukasz Gandecki} 💻 ⚠️ 📖	_{Ivan Babak} 🐛 🤔	_{Jesse Day} 💻	_{Ernesto García} 💬 💻 📖	_{Josef Maxx Blake} 💻 📖 ⚠️
_{Michal Baranowski} 📝 ✅	_{Arthur Puthin} 📖	_{Thomas Chia} 💻 📖	_{Thiago Galvani} 📖	_Christian ⚠️	_{Alex Krolick} 💬 📖 💡 🤔	_{Johann Hubert Sonntagbauer} 💻 📖 ⚠️
_{Maddi Joyce} 💻	_{Ryan Vice} 📖	_{Ian Wilson} 📝 ✅	_Daniel 🐛 💻	_{Giorgio Polvara} 🐛 🤔	_{John Gozde} 💻	_{Sam Horton} 📖 💡 🤔
_{Richard Kotze (mobile)} 📖	_{Brahian E. Soto Mercedes} 📖	_{Benoit de La Forest} 📖	_Salah 💻 ⚠️	_{Adam Gordon} 🐛 💻	_{Matija Marohnić} 📖	_{Justice Mba} 📖
_{Mark Pollmann} 📖	_{Ehtesham Kafeel} 💻 📖	_{Julio Pavón} 💻	_{Duncan L} 📖 💡	_{Tiago Almeida} 📖	_{Robert Smith} 🐛	_{Zach Green} 📖
_dadamssg 📖	_{Yazan Aabed} 📝	_Tim 🐛 💻 📖 ⚠️	_{Divyanshu Maithani} ✅ 📹	_{Deepak Grover} ✅ 📹	_{Eyal Cohen} 📖	_{Peter Makowski} 📖
_{Michiel Nuyts} 📖	_{Joe Ng'ethe} 💻 📖	_Kate 📖	_Sean 📖	_{James Long} 🤔 📦	_{Herb Hagely} 💡	_{Alex Wendte} 💡
_{Monica Powell} 📖	_{Vitaly Sivkov} 💻	_{Weyert de Boer} 🤔 👀	_EstebanMarin 📖	_{Victor Martins} 📖	_{Royston Shufflebotham} 🐛 📖 💡	_chrbala 💻
_{Donavon West} 💻 📖 🤔 ⚠️	_{Richard Maisano} 💻	_{Marco Biedermann} 💻 🚧 ⚠️	_{Alex Zherdev} 🐛 💻	_{André Matulionis dos Santos} 💻 💡 ⚠️	_{Daniel K.} 🐛 💻 🤔 ⚠️	_{mohamedmagdy17593} 💻
_{Loren ☺️} 📖	_{MarkFalconbridge} 🐛 💻	_Vinicius 📖 💡	_{Peter Schyma} 💻	_{Ian Schmitz} 📖	_{Joel Marcotte} 🐛 ⚠️ 💻	_{Alejandro Dustet} 🐛
_{Brandon Carroll} 📖