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.
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.
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.
An installation using yarn.
An installation using npm.
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.
Here’s a good read on How to Migrate from Enzyme to React Testing Library!
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.
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:
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.
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.
npm installation for Macs, Linux and Windows
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.
With npm, install globally:
You can use these development dependencies in your project:
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.
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:
If your project requires plugins, install them as follows:
First, we will install the Chai library using npm:
We can also use yarn to install Chai, the code snippet is:
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.
To install Puppeteer, you can use npm:
After installation, you can use Puppeteer in your tests by requiring it:
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.
To install Jasmine, you can use npm:
After installation, you can use Jasmine in your tests by creating a spec file:
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.
To install React Test Utils, you can use npm:
After installation, you can use React Test Utils in your tests by requiring it:
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.
To install Test Renderer, you can use npm:
After installation, you can use Test Renderer in your tests by requiring it:
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!