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)
1
Part 1 – Exploring the TDD Workflow
10
Part 2 – Building Application Features
16
Part 3 – Interactivity
20
Part 4 – Behavior-Driven Development with Cucumber

Studying the Spec Logo user interface

The interface has two panes: the left pane is the drawing pane, which is where the output from the Logo script appears. On the right side is a prompt where the user can edit instructions:

Figure 14.1: The Spec Logo interface

Look at the screenshot. You can see the following:

  • The script name in the top-left corner. This is a text field that the user can click on to change the name of the current script.
  • The display, which shows script output on the left-hand side of the page. You can see a shape has been drawn here, which is the result of the Logo statements entered at the prompt.
  • The turtle, shown in the middle of the screen. This is a little green triangle that marks where drawing commands originate. The turtle has an x and y position, starting at 0,0, which is the middle of the screen. The viewable drawing is 600x600 in size, and the turtle can move throughout this area. The turtle also has an angle, initially...