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

Designing a WebSocket interaction

In this section, we’ll start by describing the sharing workflow, then we’ll look at the new UI elements that support this workflow, and finally we’ll walk through the code changes you’ll make in this chapter.

The sharing workflow

A sharing session is made up of one presenter and zero or more watchers. That means there are two modes that the app can be in: either presenting or watching.

When the app is in presenting mode, then everyone watching will get a copy of your Spec Logo instructions. All your instructions are sent to the server via a WebSocket.

When your app is in watching mode, a WebSocket receives instructions from the server and immediately outputs them onto your screen.

The messages sent to and from the server are simple JSON-formatted data structures.

Figure 16.1 shows how the interface looks when it’s in presenter mode.

Figure 16.1 – Spec Logo in presenter...