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

Using data tables to perform setup

In this section, we’ll look at a useful time-saving feature of Cucumber: data tables. We’ll write a second scenario that, as with the previous one, will already pass given the existing implementation of Spec Logo:

  1. Create a new feature file called features/drawing.feature with the following content. It contains a set of instructions to draw a square using a Logo function. A small side length of 10 is used; that’s to make sure the animation finishes quickly:
    Feature: Drawing
      A user can draw shapes by entering commands
      at the prompt.
      Scenario: Drawing functions
        Given the user navigated to the application page
        When the user enters the following instructions at the prompt:
          | to drawsquare |
          |   repeat 4 [ forward 10 right 90 ] |