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)

Cypress-driven development

In the previous section, we installed the Cypress Testing Library and refactored an existing test for a checkout flow. In this section, we will use Cypress to drive the development of new features for an existing blog application created with Next.js. Next.js is a popular framework that provides a pleasant experience for teams to build static or server-rendered React applications.

Example features that Next.js provides are out-of-the-box routing, built-in CSS support, and API routes. Please see the Next.js documentation (https://nextjs.org/) for more details. The MY BLOG application currently has two pages, a Home page displaying all blog posts and a page to display blog details. The page that displays a list of posts looks as follows:

Figure 7.10 – Blog home page

In the previous screenshot, the Home page displays two blog posts, I love React and I love Angular. Blog data is stored in a MongoDB database and sent to the frontend...