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

Building the GraphQL reducer

The Git tag for this section is query-customer-reducer.

Now that we have a Relay environment, we can begin to build out our feature. Recall from the introduction that we're going to build a new CustomerHistory component that displays customer details and a list of the customer's appointments. A GraphQL query to return this information already exists in our server, so we just need to call it in the right way. The query itself looks like this:

customer(id: $id) {
id
firstName
lastName
phoneNumber
appointments {
startsAt
stylist
service
notes
}
}

This essentially means we get a customer record for a given customer ID (specified by the $id parameter), together with a list of their appointments.

Since our application uses Redux for data access, we'll continue to use it in this section, and we'll use Relay directly within...