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@testing-library/react-native
Advanced tools
Simple and complete React Native testing utilities that encourage good testing practices.
@testing-library/react-native is a testing library for React Native applications. It provides utilities to test React Native components in a way that resembles how users interact with your app. The library encourages writing tests that are more maintainable and less coupled to the implementation details of the components.
Rendering Components
This feature allows you to render React Native components and query them for assertions. The example demonstrates rendering a simple Text component and verifying its content.
const { render } = require('@testing-library/react-native');
const { Text } = require('react-native');
const { getByText } = render(<Text>Hello, World!</Text>);
expect(getByText('Hello, World!')).toBeTruthy();
Fire Events
This feature allows you to simulate user interactions such as pressing a button. The example shows how to render a Button component and simulate a press event.
const { render, fireEvent } = require('@testing-library/react-native');
const { Button } = require('react-native');
const handlePress = jest.fn();
const { getByText } = render(<Button title="Press me" onPress={handlePress} />);
fireEvent.press(getByText('Press me'));
expect(handlePress).toHaveBeenCalled();
Async Utilities
This feature provides utilities to handle asynchronous operations in your components. The example demonstrates how to wait for a state change in a component that updates after a timeout.
const { render, waitFor } = require('@testing-library/react-native');
const { useEffect, useState } = require('react');
const { Text } = require('react-native');
const AsyncComponent = () => {
const [data, setData] = useState(null);
useEffect(() => {
setTimeout(() => {
setData('Loaded');
}, 1000);
}, []);
return <Text>{data}</Text>;
};
const { getByText } = render(<AsyncComponent />);
await waitFor(() => expect(getByText('Loaded')).toBeTruthy());
Enzyme is a JavaScript testing utility for React that makes it easier to test your React Components' output. It provides a more detailed API for interacting with components, but it is more tightly coupled to the implementation details compared to @testing-library/react-native.
React Test Renderer is a package from the React team that allows you to render React components to pure JavaScript objects without depending on the DOM or a native mobile environment. It is useful for snapshot testing but does not provide the user-centric querying and event simulation features of @testing-library/react-native.
Jest is a delightful JavaScript Testing Framework with a focus on simplicity. While Jest itself is not specific to React Native, it is often used in conjunction with @testing-library/react-native for assertions and mocking. Jest provides a comprehensive testing solution but lacks the specific utilities for interacting with React Native components that @testing-library/react-native offers.
Simple 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 lightweight solution for testing React Native components. It provides light utility functions on top of react-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 by React 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
yarn add --dev @testing-library/react-native
npm
npm install --save-dev @testing-library/react-native
This library has a peerDependencies
listing for react-test-renderer
. Make sure that your react-test-renderer
version matches exactly the react
version.
You can use the built-in Jest matchers by adding the following line to your jest-setup.ts
file (configured using setupFilesAfterEnv
):
import '@testing-library/react-native/extend-expect';
We generally advise using the "react-native" preset when testing with this library.
However, if you use React Native version earlier than 0.71 with modern Jest fake timers (default since Jest 27), you'll need to apply this custom Jest preset or otherwise awaiting promises, like using waitFor
or findBy*
, queries will fail with a timeout.
This is a known issue. It happens because React Native's Jest preset overrides native Promise. Our preset restores it to defaults, which is not a problem in most apps out there.
Here's how you apply a custom preset in your Jest config:
{
"preset": "@testing-library/react-native"
}
If this doesn't work for you, please fall back to using "legacy" fake timers.
Note for Flow users – you'll also need to install typings for react-test-renderer
:
flow-typed install react-test-renderer
import { render, screen, fireEvent } from '@testing-library/react-native';
import { QuestionsBoard } from '../QuestionsBoard';
test('form submits two answers', () => {
const allQuestions = ['q1', 'q2'];
const mockFn = jest.fn();
render(<QuestionsBoard questions={allQuestions} onSubmit={mockFn} />);
const answerInputs = screen.getAllByLabelText('answer input');
fireEvent.changeText(answerInputs[0], 'a1');
fireEvent.changeText(answerInputs[1], 'a2');
fireEvent.press(screen.getByText('Submit'));
expect(mockFn).toBeCalledWith({
1: { q: 'q1', a: 'a1' },
2: { q: 'q2', a: 'a2' },
});
});
You can find the source of QuestionsBoard
component and this example here.
The public API of @testing-library/react-native
is focused around these essential methods:
render
– deeply renders the given React element and returns helpers to query the output components.fireEvent
- invokes named event handler on the element.waitFor
- waits for non-deterministic periods of time until the queried element is added or times out.waitForElementToBeRemoved
- waits for non-deterministic periods of time until the queried element is removed or times out.within
- creates a queries object scoped for a given element.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 at hello@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 by Rally Health.
FAQs
Simple and complete React Native testing utilities that encourage good testing practices.
The npm package @testing-library/react-native receives a total of 649,497 weekly downloads. As such, @testing-library/react-native popularity was classified as popular.
We found that @testing-library/react-native demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 15 open source maintainers collaborating on the project.
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