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 Enzyme

In the previous section, we learned how to update production dependencies and add component tests to legacy applications. In this section, we will learn how to replace existing legacy tests written in Enzyme with React Testing Library. Before React Testing Library was created, Enzyme was a popular library to test the UI of React components. Enzyme is a great tool, but the design of the API allows the implementation details of components to be tested, resulting in developers having to update test code frequently as they update their source code. We will replace legacy Enzyme tests with React Testing Library to resolve the problem of having to update tests that focus on implementation details continually.

We will use this approach to refactor legacy Enzyme tests to keep the current tests while installing and incrementally refactoring them with React Testing Library. Please refer to Chapter 2, Working with React Testing Library, for installation...