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

Manually testing our changes

The words manual testing should strike fear into the heart of every TDDer because it takes up so much time. Avoid it when you can. Of course, we can’t avoid it entirely – when we’re done with a complete feature, we need to give it a once-over to check we’ve done the right thing.

As it stands, we can’t yet run our app. To do that, we’ll need to add an entry point and then use webpack to bundle our code.

Adding an entry point

React applications are composed of a hierarchy of components that are rendered at the root. Our application entry point should render this root component.

We tend to not test-drive entry points because any test that loads our entire application can become quite brittle as we add more and more dependencies into it. In Part 4, Behavior-Driven Development with Cucumber, we’ll look at using Cucumber tests to write some tests that will cover the entry point.

Since we aren’...