Book Image

Mastering React Test-Driven Development

By : Daniel Irvine
Book Image

Mastering React Test-Driven Development

By: Daniel Irvine

Overview of this book

Many programmers are aware of TDD but struggle to apply it beyond basic examples. This book teaches how to build complex, real-world applications using Test-Driven Development (TDD). It takes a first principles approach to the TDD process using plain Jest and includes test-driving the integration of libraries including React Router, Redux, and Relay (GraphQL). Readers will practice systematic refactoring while building out their own test framework, gaining a deep understanding of TDD tools and techniques. They will learn how to test-drive features such as client- and server-side form validation, data filtering and searching, navigation and user workflow, undo/redo, animation, LocalStorage access, WebSocket communication, and querying GraphQL endpoints. The book covers refactoring codebases to use the React Router and Redux libraries. via TDD. Redux is explored in depth, with reducers, middleware, sagas, and connected React components. The book also covers acceptance testing using Cucumber and Puppeteer. The book is fully up to date with React 16.9 and has in-depth coverage of hooks and the ‘act’ test helper.
Table of Contents (21 chapters)
Free Chapter
1
Section 1: First Principles of TDD
6
Section 2: Building a Single-Page Application
12
Section 3: Interactivity
16
Section 4: Acceptance Testing with BDD

Isolating components for animation

There are two parts to this animation:

  • First, there's a movement animation that occurs when lines are being drawn. Say, for example, that the user has entered forward 100 as an instruction. We want the turtle to move slowly 100 units along, at a given speed. As it moves, it will draw the line behind it.
  • The second animation is turtle rotation. The turtle does not turn instantly; if the user types rotate 90 then the turtle should rotate slowly until it has made a quarter turn.

The code we'll write is relatively complicated, so we need to do some up-front design first.

Designing the component

The Git tag for this section is animation.

As you read through this section, you might...