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

Not testing at all

There is a belief that TDD doesn’t apply to some scenarios in which it does – for example, if your code is throwaway or if it’s presumed to never need modification once it’s deployed. Believing this is almost ensuring the opposite is true. Code, particularly code without tests, has a habit of living on beyond its intended lifespan.

Fear of deleting code

In addition to reducing the fear of changing code, tests also reduce the fear of removing code. Without tests, you’ll read some code and think “maybe something uses this code for some purpose I don’t quite remember.” With tests in place, this won’t be a concern. You’ll read the test, see that the test no longer applies due to a changed requirement, and then delete the test and its corresponding production code.

However, there are several scenarios in which not writing tests is acceptable. The two most important ones are as follows.