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

Testing the data source of a table view

In this section, we will implement parts of the data source for the table view using test-driven development. We will use the traditional approach by using the view controller as the data source. In the next section, we will switch to a diffable data source. Our challenge in this section is to write the tests so that they are independent of the actual implementation of the data source.

But first, we need to talk about test doubles.

Adding a test double

In the film industry, doubles are used in scenes that are too dangerous for the actor. The double must look and act like the actor. In software testing, we have something similar: test doubles. Test doubles look and act like a piece of code, but can be controlled completely from within the test. For example, to test the data source of our table view, we need to connect the view controller with a store of to-do items. We could use the store we already implemented. But this would make the...