Learn how to test React applications with Jest and React Testing Library, a popular combination and official recommendation from React.

Testing is an essential practice in software engineering. It helps build robust and high-quality software and boosts the team’s confidence in the code, making the application more flexible and prone to fewer errors when introducing or modifying features.

Highly efficient teams make testing a core practice in their everyday routines, and no feature is released before automated tests are in place. Some developers even write the tests before writing the features, following a process called TDD (Test Driven Development).

In this article, we’ll test React applications with Jest and React Testing Library, a popular combination of a JavaScript testing framework and a React utility for testing components. It’s also the official recommendation given on React’s documentation.

What is testing?

Testing is the process of automating assertions between the results the code produces and what we expect the results to be.

When testing React applications, our assertions are defined by how the application renders and responds to user interactions.

There are many different types of testing paradigms and philosophies. This article will focus on creating unit and component tests (or integration tests).

Introduction to Jest and React Testing Library

What is Jest?

Jest is a JavaScript testing framework that allows developers to run tests on JavaScript and TypeScript code and integrates well with React.

It’s a framework designed with simplicity in mind and offers a powerful and elegant API to build isolated tests, snapshot comparison, mocking, test coverage, and much more.

React Testing Library

React Testing Library is a JavaScript testing utility built specifically for testing React components. It simulates user interactions on isolated components and asserts their outputs to ensure the UI is behaving correctly.

#react #javascript #testing #jest