Top React Testing Libraries you should know about

In recent years, React, a popular JavaScript library has become one of the most widely used frameworks for web development. And as React applications become more complex, the need for comprehensive testing will also grow.

The React community has provided multiple libraries to test React components in the app, making it easier for developers to write and run tests efficiently. These libraries and frameworks come with a variety of features, from simple unit testing to end-to-end testing, making it easier to test different aspects of your application. But with so many options available, it can be challenging to choose the right testing framework for your project.

As we move forward into 2023, it's essential to stay up-to-date with the latest and most powerful testing libraries and tools available in the React community. In this article, we'll explore some of the best React testing libraries and frameworks that developers can use to ensure their applications are bug-free and perform as intended.

1. Jest

Jest has solidified its position as one of the  most popular React sting frameworks available in the market today. Developed by Facebook, Jest has been designed to provide a seamless testing experience for React developers. The framework supports TypeScript, Node.js, Angular, and Vue.js, in addition to React, which is a testament to its versatility.

Jest is a go-to testing framework for many companies like Uber, Airbnb, and Facebook, making it a popular choice among React developers. This React library offers features like UI snapshot testing, code coverage, and more, along with an extensive API tailored to React. All this makes Jest the preferred testing framework among the React community.

One of the significant advantages of Jest is that it supports most JavaScript projects right from the start, including create-react-app, NG, Vue, TypeScript, and Babel, which helps developers save time and effort. Moreover, the process-based parallel testing feature of Jest is easy to use and offers the flexibility of prioritizing failed tests.

Another noteworthy feature of Jest is its ease of use. Setting up Jest is a breeze, and it's readily available on Node Package Manager (NPM). Developers familiar with JavaScript can start writing Jest tests without much hassle.

Jest's comprehensive features, ease of use, and performance advantages make it a top-tier React testing library in the market today. It's no surprise that it's the most popular testing framework for React, with over 16 million downloads per week.

Why is Jest popular?

• The Jest snapshot capturing feature makes it easier to keep track of large test cases.
• Jest also supports parallelization and async method tests, allowing faster and more efficient testing processes.
• Another reason for its popularity is its ease of use and has zero setup requirement, making it accessible to developers of all skill levels.
• With its excellent performance and standard syntax, Jest provides a comprehensive report guide for better understanding and analyzing test results.

Installation

An installation using yarn.

yarn add --dev jest

An installation using npm.

npm install --save-dev jest

2. React Testing Library

React Testing Library is a popular testing library used by many companies, including Graphy, Ze Delivery, Commercetools, Hivebrite, MPB, Page Builder, and others.

The library is designed to simulate user behaviour in tests, making it easier to test components. Its comprehensive set of React DOM testing utilities allows developers to simulate real user action and workflow. With the React Testing Library, developers can easily test their React components.

React Testing Library is a library that provides a set of utilities for testing React components in a way that closely mimics how users interact with the application. It is built on top of the DOM Testing Library, which provides a set of generic utilities for testing DOM nodes.

One of the main benefits of using React Testing Library is that it provides a simple and intuitive API for testing React components. With the library's approach, developers can focus on testing the behaviour of their components rather than implementation details. This approach also promotes more resilient tests as they are less likely to break due to implementation changes.

While the library has some limitations, including the inability to perform shallow rendering or access state-based information, it provides an excellent solution for testing components from the user's perspective. The React Testing Library has gained significant popularity in the React community and is an excellent choice for testing React components.

Why is React Testing Library popular?

• Developers can use utilities to easily write tests in React Testing Library, without any experience with testing frameworks.
• It is well-suited for unit and integration testing, offering a comprehensive set of DOM testing utilities.
• It can be seamlessly integrated with popular frameworks like React, Angular, and Vue, making it a versatile option for testing various types of applications.
• One of its most significant advantages is that refactoring components does not break the tests.
• It is backed by a large community of developers who actively contribute and support the library.

Here’s a good read on How to Migrate from Enzyme to React Testing Library!

Installation

npm installation

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

Yarn installation

yarn add --dev @testing-library/react

3. Enzyme

Enzyme is a well known testing utility that simplifies the process of testing React components by abstracting the rendering process. The framework is often used in conjunction with Jest. Other React testing libraries like Karma and Mocha also use Enzyme.

Enzyme's ability to manipulate, traverse, and simulate runtime components makes it a powerful tool for finding and interacting with DOM elements. Like JQuery's manipulation of DOM elements, Enzyme also manipulates, traverses, and even pretends to be a runtime element.

Companies like Frontend, BlaBlaCar, and Kaidee use it for testing their applications. Airbnb is among leading contributors and maintainers of Enzyme, and even uses it in their own workflows.

Over all, Enzyme is an excellent choice for developers who want a powerful, easy-to-use tool for testing their React components.

Why is Enzyme popular?

• Enzyme is easy to use and works smoothly with testing libraries like Jest, Mocha, and Karma, making it the top choice for testing almost one-third of React applications.
• Enzyme offers shallow rendering and full DOM rendering options for testing React components.
• With Enzyme, developers can access React components to conduct testing.
• The utility provides detailed error reporting that helps with identifying and resolving issues quickly.

Installation

To begin using the enzyme, one simply needs to install it using the npm package manager. However, if one is using React or another UI Component library, one will also need to install an adapter along with enzyme. Enlisted below is an example of how to use enzyme with React 16:

npm i --save-dev enzyme enzyme-adapter-react-16

Each adapter that is in use may have additional peer dependencies, so one may need to install them as well.

One major drawback of Enzyme is that it only supports up to React 16. Enzyme has not been updated to support newer versions of React such as React 18, which introduced improvements like automatic batching, fresh new APIs like startTransition, and also streaming server-side rendering with support for Suspense.

4. Cypress

Cypress is an end-to-end testing framework that simplifies and enhances the process of setting up, writing, running, and debugging browser tests for any front-end framework. It is built on Mocha, a feature-rich JavaScript test framework that can run on and in the browser, making it easy to perform asynchronous testing.

The Cypress testing library is also equipped with behaviour-driven development (BDD) and test-driven development (TDD) assertion library, which can be paired with any JavaScript testing framework. With Cypress, developers can quickly write and execute tests, using familiar APIs and native browser features, such as automated screenshots, real-time reloading, and network traffic control.

One of the key features of Cypress is its ability to run tests in the browser, allowing developers to debug their tests easily and efficiently. This makes it an ideal choice for testing web applications, as it allows developers to simulate real-world scenarios and interactions in the browser environment.

Additionally, Cypress has a simple and intuitive user interface that enables developers to write and execute tests using a variety of tools, such as the Cypress Test Runner, a command-line interface (CLI), and an integrated development environment (IDE) plugin.

Overall, Cypress is a reliable and efficient testing framework that streamlines the testing process and makes it easier for developers to ensure the quality and reliability of their front-end applications.

Why is Cypress popular?

• Easy to setup and run tests.
• Low test writing time as compared to other frameworks.
• Integrates with any CI tool that supports headless execution with command-line options.
• Automatically captures screenshots of test execution in case of test failure for effective debugging.
• Automatically reloads the Test Runner once changes have been made to the test.

Installation

npm installation for Macs, Linux and Windows

npm install cypress --save-dev

Yarn install

yarn add cypress --dev

5. Mocha

Mocha is a JavaScript testing framework that can run on Node.js and in web browsers. It works with asynchronous testing and provides detailed reporting by running tests one after the other.

Mocha also maps any uncaught exceptions to the appropriate test cases for better error tracking. Developers can customize their testing tools and include or exclude supporting libraries with Mocha's flexibility.

Mocha can also be used with Enzyme, Chai, and other libraries for assertions and mocking when testing React applications, similar to other testing frameworks like Jest. However, for more advanced configurations, some developers prefer to use Mocha with a rich toolset.

One drawback of using Mocha for React testing is that it may require additional tools in the workflow for common tasks like snapshots.

Why is Mocha popular?

• Supports testing of asynchronous code
• Can be used for testing both server-side and client-side applications
• Offers high flexibility for customization and configuration
• Has extensive documentation and a wide range of tutorials available for learning and troubleshooting

Installation

With npm, install globally:

$ npm install --global mocha

You can use these development dependencies in your project:

$ npm install --save-dev mocha

6. Karma

Karma allows you to execute JavaScript programs and test them in real time on multiple browsers. You can conduct tests on real browsers and devices, including mobile phones, tablets, and desktops while receiving feedback directly in your IDE.

The test runner in Karma runs on an HTTP server that generates the HTML file. It is also compatible with continuous deployment tools such as Jenkins, Travis, and others.

Karma is compatible with React testing frameworks or assertion libraries, but it also works well with Jasmine, Mocha, and other similar libraries.

Why is Karma popular?

• Karma allows performing cross-browser testing.
• Supports continuous integration and deployment to Jenkins, Travis, and CircleCI.
• Provides an easy and seamless way to write code and obtain feedback from tests
• Has extensive community support and numerous plugins available

Installation

The Karma package runs on Node.js and is accessible via npm. To install Karma and its required plugins in your project directory, follow the steps below for a local installation. Karma must be installed by:

$ npm install karma --save-dev

If your project requires plugins, install them as follows:

$ npm install karma-jasmine karma-chrome-launcher jasmine-core --save-dev

7. Chai

Chai is an assertion library for JavaScript that provides a wide range of assertion styles and interfaces. It can be used for testing any JavaScript code, not just React components.

Why is Chai popular?

• Easy to use and learn.
• Lightweight and makes it easy to integrate into existing projects.
• Compatible with any testing framework and can be easily customized to meet specific testing requirements.

Installation

First, we will install the Chai library using npm:

npm install chai

We can also use yarn to install Chai, the code snippet is:

yarn add chai

8. Puppeteer

Puppeteer is a Nodejs library which was developed by Google and lets you control headless Chrome, which is a way of running chrome without a Graphical User Interface, through the dev tools Protocol. It also provides a high-level API for controlling a headless Chrome browser, which makes it easy to simulate user interactions and test the behaviour of your React components.

Why is Puppeteer popular?

• It allows for the testing of both client-side and server-side rendering of React components.
• Puppeteer can be used to test complex user flows that involve multiple pages and interactions.
• The library provides powerful debugging tools that make it easy to diagnose and fix issues in your tests.
• Puppeteer has built-in support for testing accessibility features of your React components.

Installation

To install Puppeteer, you can use npm:

npm i puppeteer

After installation, you can use Puppeteer in your tests by requiring it:

const puppeteer = require('puppeteer');

9. Jasmine

Jasmine is a well-known testing framework that is suitable for testing React applications. It offers a user-friendly and straightforward API for creating tests and has a significant community of contributors that participate in its advancement.

Why is Jasmine popular?

• Jasmine provides a BDD-style syntax that is easy to read and write, making it easy to write tests for React components.
• The framework supports both synchronous and asynchronous testing.
• Jasmine provides a range of built-in matchers that makes it easy to test the behavior of React components.
• The framework has a large and active community of developers, which means that there are many resources available for learning about this library.

Installation

To install Jasmine, you can use npm:

npm install --save-dev jasmine

After installation, you can use Jasmine in your tests by creating a spec file:

describe('My React Component', () => {
  it('should render correctly', () => {
    // Write your test code here
  });
});

10. React Test Utils

React Test Utils provides a simple and intuitive API for testing React components, and is built on top of the React library itself, which means that it is tightly integrated with React and is optimized for testing React components.

Why is React Test Utils popular?

• React Test Utils provides a range of built-in utilities for testing React components, including shallow rendering and simulation of user interactions.
• The library provides a simple and intuitive API that is easy to learn and use.
• It is built on top of the React library, which means it is tightly integrated with React and is optimized for testing React components.
• The library is compatible with other testing frameworks, such as Jasmine and Mocha.

Installation

To install React Test Utils, you can use npm:

npm install react-test-utils --save-dev

After installation, you can use React Test Utils in your tests by requiring it:

const ReactTestUtils = require('react-test-utils');

11. Test Renderer

Test Renderer is basically a React renderer that is generally used to render React components to pure JavaScript objects, without solely depending on the DOM or a native mobile environment.

It also provides a lightweight and simple API for testing React components. It is designed to be used in conjunction with Jest, but can also be used with other testing frameworks.

Essentially, this package makes it easy to grab a snapshot of the platform view hierarchy (similar to a DOM tree) rendered by a React DOM or React Native component without using a browser or jsdom.

Why is Test Renderer popular?

• Test Renderer provides a lightweight and simple API that is easy to use and understand.
• The library is designed to work with React's virtual DOM, which makes it an excellent tool for testing React components that do not require a full DOM environment.
• Test Renderer is compatible with Jest, a popular testing framework for React applications, which means that it can be easily integrated into existing test suites.
• The library is also compatible with other testing frameworks, such as Mocha and Jasmine.

Installation

To install Test Renderer, you can use npm:

npm install react-test-renderer --save-dev

After installation, you can use Test Renderer in your tests by requiring it:

const TestRenderer = require('react-test-renderer');

Conclusion

Developers have too many choices when it comes to selecting a React testing library for their applications. Settling down with a single library can be a hard call, but you don't have to take it. You can combine these testing frameworks and assertion/manipulation libraries to create test-driven development with a flexible and adaptable workflow.

If you are starting with React, generally speaking, React testing library can be your go-to framework. But that should not stop you from experimenting with other libraries as you grow.

Now that you have a decent understanding of React testing libraries, a good next step would be to learn how to write Unit Tests for your React app!

Happy coding!