Preface

Automatic tests are an essential part of agile software development, especially unit tests, with their quick and reliable feedback helping developers to keep projects maintainable and clean. Test-driven development (TDD) methodology gives developers clear rules about how to build scalable, maintainable, and – as such – agile projects. Often, once the initial aversion to writing tests before the code is overcome, developers stick to TDD because they feel that their code is better and they are more confident in the result.

In this book, we will explore how to write unit tests for many different aspects of iOS development for iOS 15+. All that will be done in the context of test-driven development. The book starts with an introduction to testing in general and TDD in iOS apps and continues with building a complete app throughout the book. It covers basic UI structures, the Combine framework, async/await, and even SwiftUI.

After you've worked through the book and challenged yourself in the exercises, you will be able to write tests for a variety of code in iOS development, and you will have the tools to decide what to learn next in your journey to become an expert in test-driven iOS development.