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Developer-friendly and complete React Native testing utilities that encourage good testing practices.

You want to write maintainable tests for your React Native 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 tests 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.

The React Native Testing Library (RNTL) is a comprehensive solution for testing React Native components. It provides React Native runtime simulation on top ofreact-test-renderer, 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.

This project is inspired byReact Testing Library. Tested to work with Jest, but it should work with other test runners as well.

Open a Terminal in your project's folder and run:

# Yarn install:yarn add --dev @testing-library/react-native# NPM installnpm install --save-dev @testing-library/react-native

This library has apeerDependencies listing forreact-test-renderer. Make sure that yourreact-test-renderer version matches exactly thereact version, avoid using^ in version number.

You can use the built-in Jest matchers automatically by having any import from@testing-library/react-native in your test.

import{render,screen,userEvent}from'@testing-library/react-native';import{QuestionsBoard}from'../QuestionsBoard';// It is recommended to use userEvent with fake timers// Some events involve duration so your tests may take a long time to run.jest.useFakeTimers();test('form submits two answers',async()=>{constquestions=['q1','q2'];constonSubmit=jest.fn();constuser=userEvent.setup();render(<QuestionsBoardquestions={questions}onSubmit={onSubmit}/>);constanswerInputs=screen.getAllByLabelText('answer input');// simulates the user focusing on TextInput and typing text one char at a timeawaituser.type(answerInputs[0],'a1');awaituser.type(answerInputs[1],'a2');// simulates the user pressing on any pressable elementawaituser.press(screen.getByRole('button',{name:'Submit'}));expect(onSubmit).toHaveBeenCalledWith({1:{q:'q1',a:'a1'},2:{q:'q2',a:'a2'},});});

You can find the source ofQuestionsBoard component and this examplehere.

React Native Testing Library consists of following APIs:

• render function - render your UI components for testing purposes
• screen object - access rendered UI:
  • Queries - find rendered components by various predicates: role, text, test ids, etc
  • Lifecycle methods:rerender,unmount
  • Helpers:debug,toJSON,root
• Jest matchers - validate assumptions about your UI
• User Event - simulate common user interactions likepress ortype in a realistic way
• Fire Event - simulate any component event in a simplified way
• renderHook function - render hooks for testing purposes
• Miscellaneous APIs:
  • Async utils:findBy* queries,waitFor,waitForElementToBeRemoved
  • Configuration:configure,resetToDefaults
  • Accessibility:isHiddenFromAccessibility
  • Other:within,act,cleanup

• Migration to 13.0
• Migration to built-in Jest Matchers

• Troubleshooting guide

Check out our list ofCommunity Resources about RNTL.

React Native Testing Library is an open source project and will always remain free to use. If you think it's cool, please star it 🌟.Callstack is a group of React and React Native geeks, contact us athello@callstack.com if you need any help with these or just want to say hi!

Like the project? ⚛️Join the team who does amazing stuff for clients and drives React Native Open Source! 🔥

Supported and used byRally Health.