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 animation

As you read through this section, you may wish to open src/Drawing.js and read the existing code to understand what it’s doing.

The current Drawing component shows a static snapshot of how the drawing looks at this point. It renders a set of Scalable Vector Graphics (SVG) lines to represent the path the turtle has taken to this point, and a triangle to represent the turtle.

The component makes use of two child components:

  • The Turtle component is displayed once and draws an SVG triangle at the given location
  • The StaticLines component is a set of SVG lines that are drawn onscreen to represent the drawn commands

We will add a new AnimatedLine component that represents the current line being animated. As lines complete their animation, they will move into the StaticLines collection.

We’ll need to do some work to convert this from a static view to an animated representation.

As it stands, the component takes a turtle prop...