Book Image

Mastering React Test-Driven Development - Second Edition

By : Daniel Irvine
Book Image

Mastering React Test-Driven Development - Second Edition

By: Daniel Irvine

Overview of this book

Test-driven development (TDD) is a programming workflow that helps you build your apps by specifying behavior as automated tests. The TDD workflow future-proofs apps so that they can be modified without fear of breaking existing functionality. Another benefit of TDD is that it helps software development teams communicate their intentions more clearly, by way of test specifications. This book teaches you how to apply TDD when building React apps. You’ll create a sample app using the same React libraries and tools that professional React developers use, such as Jest, React Router, Redux, Relay (GraphQL), Cucumber, and Puppeteer. The TDD workflow is supported by various testing techniques and patterns, which are useful even if you’re not following the TDD process. This book covers these techniques by walking you through the creation of a component test framework. You’ll learn automated testing theory which will help you work with any of the test libraries that are in standard usage today, such as React Testing Library. This second edition has been revised with a stronger focus on concise code examples and has been fully updated for React 18. By the end of this TDD book, you’ll be able to use React, Redux, and GraphQL to develop robust web apps.
Table of Contents (26 chapters)
Part 1 – Exploring the TDD Workflow
Part 2 – Building Application Features
Part 3 – Interactivity
Part 4 – Behavior-Driven Development with Cucumber

Up-front design for a reducer and a saga

In this section, we’ll do the usual thing of mapping out a rough plan of what we’re going to build.

Let’s start by looking at what the actual technical change is going to be and discuss why we’re going to do it.

We’re going to move the logic for submitting a customer—the doSave function in CustomerForm—out of the React component and into Redux. We’ll use a Redux reducer to manage the status of the operation: whether it’s currently submitting, finished, or had a validation error. We’ll use a Redux saga to perform the asynchronous operation.

Why Redux?

Given the current feature set of the application, there’s really no reason to use Redux. However, imagine that in the future, we’d like to support these features:

  • After adding a new customer, the AppointmentForm component shows the customer information just before submitting it, without having...