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

Exploring Test Doubles

In this chapter, we'll look at the most involved piece of the TDD puzzle: test doubles.

The unit in unit testing refers to the single function or component that we focus on for the duration of that test. The Act phase of a test should involve just one action on one unit. But units don't act in isolation: functions and components collaborate and depend on other units. Your application can be thought of as a web of dependencies, and test doubles help us to design and test those dependencies.

The following topics will be covered in this chapter:

  • What is a test double?
  • Submitting forms using spies
  • Stubbing the fetch API
  • Extracting test helpers