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

Testing useEffect and Mocking Components

In the previous chapter, you saw how test doubles can be used to verify network requests that occur upon user actions, such as clicking a submit button. We can also use them to verify side effects when our components mount, like when we're fetching data from the server that the component needs to function. In addition, test doubles can be used to verify the rendering of child components. Both use cases often occur together with container components, which are responsible for simply loading data and passing it to another component for display.

In this chapter, we’ll build a new component, AppointmentsDayViewLoader, that loads the day’s appointments from the server and passes them to the AppointmentsDayView component that we implemented in Chapter 2, Rendering Lists and Detail Views. By doing so, the user can view a list of appointments occurring today.

In this chapter, we will cover the following topics:

  • Mocking...