The Art of Unit Testing With Examples in JavaScript, 3rd Edition

Unit testing is more than just a collection of tools and practices—it’s a state of mind! This bestseller reveals the master’s secrets for delivering robust, maintainable, and trustworthy code.

Thousands of developers have learned to hone their code quality under the tutelage of The Art of Unit Testing. This revised third edition updates an international bestseller to reflect modern development tools and practices, as well as to cover JavaScript.

Inside The Art of Unit Testing, Third Edition you will learn how to:

Create readable, maintainable, and trustworthy tests
Work with fakes, stubs, mock objects, and isolation frameworks
Apply simple dependency injection techniques
Refactor legacy code with confidence
Test both frontend and backend code


Effective unit tests streamline your software development process and ensure you deliver consistent high-quality code every time. With practical examples in JavaScript and Node, this hands-on guide takes you from your very first unit tests all the way to comprehensive test suites, naming standards, and refactoring techniques. You’ll explore test patterns and organization, working with legacy code and even “untestable” code. The many tool-agnostic examples are presented in JavaScript and carefully designed so that they apply to code written in any language.

Purchase of the print book includes a free eBook in PDF, Kindle, and ePub formats from Manning Publications.

About the technology

The art of unit testing is more than just learning the right collection of tools and practices. It’s about understanding what makes great tests tick, finding the right strategy for each unique situation, and knowing what to do when the testing process gets messy. This book delivers insights and advice that will transform the way you test your software.

About the book

The Art of Unit Testing, Third Edition shows you how to create readable and maintainable tests. It goes well beyond basic test creation into organization-wide test strategies, troubleshooting, working with legacy code, and “merciless” refactoring. You’ll love the practical examples and familiar scenarios that make testing come alive as you read. This third edition has been updated with techniques specific to object-oriented, functional, and modular coding styles. The examples use JavaScript.

What's inside

Deciding on test types and strategies
Test Entry & Exit Points
Refactoring legacy code
Fakes, stubs, mock objects, and isolation frameworks
Object-Oriented, Functional, and Modular testing styles