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)

Writing Gherkin-style tests with Cucumber

In the previous section, we learned how to use Cypress to test API responses. In this section, we will learn how to create Gherkin-style tests with Cucumber. Gherkin is a behavior-driven development language used by Cucumber to describe test scenarios' behavior in a plain-English format. Tests written in Gherkin also make it easier for software teams to communicate and provide context for test cases with business leaders.

Gherkin uses the following keywords: Feature, Scenario, Given, When, and Then. Feature is used to describe the thing to build, such as a login page, for example. Scenario describes the user flow for the feature. For example, a user can enter a username, password, and click Login to navigate to their profile page.

The Given, When, and Then keywords describe the scenario at different stages. We could write a complete Gherkin test for a login feature like so:

Feature: Login
  Scenario: A user can enter...