Book Image

Test-Driven iOS Development with Swift - Fourth Edition

By : Dr. Dominik Hauser
Book Image

Test-Driven iOS Development with Swift - Fourth Edition

By: Dr. Dominik Hauser

Overview of this book

Test-driven development (TDD) is a proven way to find software bugs earlier on in software development. Writing tests before you code improves the structure and maintainability of your apps, and so using TDD in combination with Swift 5.5's improved syntax leaves you with no excuse for writing bad code. Developers working with iOS will be able to put their knowledge to work with this practical guide to TDD in iOS. This book will help you grasp the fundamentals and show you how to run TDD with Xcode. You'll learn how to test network code, navigate between different parts of the app, run asynchronous tests, and much more. Using practical, real-world examples, you'll begin with an overview of the TDD workflow and get to grips with unit testing concepts and code cycles. You'll then develop an entire iOS app using TDD while exploring different strategies for writing tests for models, view controllers, and networking code. Additionally, you'll explore how to test the user interface and business logic of iOS apps and even write tests for the network layer of the sample app. By the end of this TDD book, you'll be able to implement TDD methodologies comfortably in your day-to-day development for building scalable and robust applications.
Table of Contents (17 chapters)
Section 1 –The Basics of Test-Driven iOS Development
Section 2 –The Data Model
Section 3 –Views and View Controllers
Section 4 –Networking and Navigation

What to test

What should be tested? When using TDD and following its ideology, the answer is easy – everything. You only write production code because there is a failing test.

In practice, it's not that easy. For example, should the position and color of a button be tested? Should the view hierarchy be tested? Probably not; the color and exact position of the button is not important for the functioning of an app. In the early stages of development, these kinds of things tend to change. With Auto Layout, different screen sizes, and different localizations of apps, the exact position of buttons and labels depends on many parameters.

In general, you should test the features that make the app useful for a user and those that need to work. Users don't care whether the button is exactly 20 points from the rightmost edge of the screen. Users seek apps that are easy to understand and a joy to use.

In addition to this, you should not test the whole app at once using...