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

Summary

Cucumber tests (and acceptance tests in general) are similar to the tests we've been writing in the rest of the book. They are focused on specifying examples of behavior. They should be specific in nature: they should not talk in abstract terms, but make use of real data and numbers as a means to test a general concept, just as we've done in the two examples in this chapter. All this is in common with unit tests.

The essential difference from our unit tests is that acceptance tests are done at a much higher level. You don't need to test every single detail in your features, unlike in your unit tests, which will get all the details ironed out.

Just as with unit tests, it's important to find ways to simplify the code. The number one rule is to try to write generic Given, When, and Then phrases that can be reused across classes and extracted out of step...