Book Image

Simplify Testing with React Testing Library

By : Scottie Crump
Book Image

Simplify Testing with React Testing Library

By: Scottie Crump

Overview of this book

React Testing Library (RTL) is a lightweight and easy-to-use tool for testing the document object model (DOM) output of components. This book will show you how to use this modern, user-friendly tool to test React components, reducing the risk that your application will not work as expected in production. The book demonstrates code snippets that will allow you to implement RTL easily, helping you to understand the guiding principles of the DOM Testing Library to write tests from the perspective of the user. You'll explore the advantages of testing components from the perspective of individuals who will actually use your components, and use test-driven development (TDD) to drive the process of writing tests. As you advance, you'll discover how to add RTL to React projects, test components using the Context API, and also learn how to write user interface (UI) end-to-end tests using the popular Cypress library. Throughout this book, you’ll work with practical examples and useful explanations to be able to confidently create tests that don't break when changes are made. By the end of this React book, you will have learned all you need to be able to test React components confidently.
Table of Contents (10 chapters)

Refactoring tests written with ReactTestUtils

In the previous section, we learned how to convert tests written in Enzyme to React Testing Library. The process involved refactoring existing tests and then uninstalling the Enzyme library. In this section, we will use a similar process, only we will not have to uninstall an existing testing library. The ReactTestUtils module is included with React, so we can simply not import the module in our test file when we don't want to use it. Since the refactoring process is similar to the previous section, we will only look at one example in this section. The test we will refactor verifies that a user can set an income amount:

import React from 'react';
import ReactDOM from 'react-dom';
import { act } from 'react-dom/test-utils';
import App from './App';

In the preceding code, we import React, ReactDOM, and the act method. The act method imported from the test-utils module is used to sync component...