Preface

Initially, all processing used to happen on the server's side and simple output was the response to web browsers. Nowadays, there are so many JavaScript frameworks and libraries that help readers to create charts, animations, simulations, and so on. By the time a project finishes or reaches a stable state, so much JavaScript code has already been written that changing and maintaining it further is tedious. At this point comes the importance of automated testing, and more specifically, developing all that code in a test-driven environment. Test-driven development is a methodology that makes testing the central part of the design process—before writing code, developers decide upon the conditions that code must meet to pass a test. The end goal is to help the readers understand the importance and process of using TDD as a part of the development.

This book starts with the details of test-driven development, its importance, need, and benefits. Later, the book introduces popular tools and frameworks, such as YUI, Karma, QUnit, DalekJS, JsUnit, and so on, to utilize Jasmine, Mocha, and Karma for advanced concepts such as feature detection, server-side testing, and patterns. We are going to understand, write, run tests, and further debug our programs. The book concludes with best practices in JavaScript testing. By the end of the book, the readers will know why they should test, how to do it most efficiently, and will have a number of versatile tests (and methods to devise new tests) so they can get to work immediately.