Learn to write better automated tests that will dramatically increase your productivity and have fun while doing so. This book is a build-your-own adventure designed for individual reading and for collaborative workshops. You will build an xUnit automated test framework using JavaScript: initially a clone of Jest, but adding a couple of neat features borrowed from RSpec, the genre-defining tool for behavior-driven development (BDD). Along the way, you will explore the philosophy behind automated testing best practices. The automated test runner is one of the most important innovations within software engineering. But for many programmers, automated testing remains a mystery, and knowing how to write good tests is akin to sorcery. As the chapters of this book unfold, you will see how the humble test runner is an elegant and simple piece of software. Each chapter picks a single feature to build, like the "it" function or the "beforeEach" block. It picks apart the theory of why the feature needs to exist, and how to use it effectively in your own test suites. Every chapter ends with a set of ideas for extension points should you wish to explore further, alone or in groups. The book culminates in an implementation of test doubles and mocks-one of the most difficult and misunderstood concepts within automated testing. By the end of the book, you will have gained a solid understanding of automated testing principles that you can immediately apply to your work projects. What You'll Learn Build an xUnit automated test framework See how an automated test runner works Understand the best practices for automated unit testing Effectively use test doubles and mocks Who This Book Is For Software developers with JavaScript experience who are seeking to master the art of automated testing.

Learn test-driven and behavior-driven development techniques that will give you greater confidence when building React applications Key Features Explore the TDD process, how it works, and why it will help you write maintainable React apps Develop a component testing framework from scratch, which will help you understand the mechanics of good unit testing Reduce complexity by using unit tests and end-to-end acceptance tests to drive the design of your apps Book DescriptionTest-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. What you will learn Build test-driven applications using React 18 and Jest Understand techniques and patterns for writing great automated tests Use test doubles and mocks effectively Test-drive browser APIs, including the Fetch API and the WebSocket API Integrate with libraries such as React Router, Redux, and Relay (GraphQL) Use Cucumber.js and Puppeteer to build Behaviour- Driven Development (BDD) style tests for your applications Build and test async Redux code using redux-saga and expect-redux Who this book is forThis book is for frontend developers who are looking to improve their testing practices and increase the quality and maintainability of their applications. To make the most of this book, you'll need knowledge of the JavaScript programming language.

Implement TDD for your React applications using Jest, React Router, Redux, and GraphQL/Relay. Learn BDD and end-to-end acceptance testing with CucumberJS and Puppeteer. Key Features Learn the TDD process using the React framework Build complex, real-world applications with a pragmatic approach to TDD Use Cucumber for acceptance and BDD testing, bringing TDD to the wider team Book DescriptionMany 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. What you will learn Build test-driven applications using React 16.9+ and Jest Build complete web applications using a variety of HTML input elements Understand the different types of test double and when to apply them Test-drive the Integration of libraries such as React Router, Redux, and Relay (GraphQL) Learn when to be pragmatic and how to apply TDD shortcuts Test-drive interaction with browser APIs including fetch and WebSocket Use Cucumber.js and Puppeteer to build BDD-style acceptance tests for your applications Build and test async Redux code using redux-saga and expect-redux Who this book is forThe target audience for this book is JavaScript developers who are looking to implement test-driven and behavior-driven approaches for their React applications.