Book Image

SwiftUI Cookbook

By : Giordano Scalzo, Edgar Nzokwe
Book Image

SwiftUI Cookbook

By: Giordano Scalzo, Edgar Nzokwe

Overview of this book

SwiftUI is an innovative and simple way to build beautiful user interfaces (UIs) for all Apple platforms, right from iOS and macOS through to watchOS and tvOS, using the Swift programming language. In this recipe-based book, you’ll work with SwiftUI and explore a range of essential techniques and concepts that will help you through the development process. The recipes cover the foundations of SwiftUI as well as the new SwiftUI 2.0 features introduced in iOS 14. Other recipes will help you to make some of the new SwiftUI 2.0 components backward-compatible with iOS 13, such as the Map View or the Sign in with Apple View. The cookbook begins by explaining how to use basic SwiftUI components. Then, you’ll learn the core concepts of UI development such as Views, Controls, Lists, and ScrollViews using practical implementation in Swift. By learning drawings, built-in shapes, and adding animations and transitions, you’ll discover how to add useful features to the SwiftUI. When you’re ready, you’ll understand how to integrate SwiftUI with exciting new components in the Apple development ecosystem, such as Combine for managing events and Core Data for managing app data. Finally, you’ll write iOS, macOS, and watchOS apps while sharing the same SwiftUI codebase. By the end of this SwiftUI book, you'll have discovered a range of simple, direct solutions to common problems found in building SwiftUI apps.
Table of Contents (15 chapters)

Unit testing an app based on Combine

I must confess that the topic of this recipe is very close to my heart: unit testing an app based on Combine.

We are going to implement an app that retrieves a list of GitHub users and shows them in a list view.

The code is pretty similar to the one in the Fetching remote data using Combine and visualizing it in SwiftUI recipe, but in this case we'll see how to unit test it—something that, even if it is very important, isn't well covered in documentation and tutorials.

Getting ready

Let's open Xcode and create a SwiftUI app called GithubUsersApp, paying attention to enabling the Unit Tests:

Figure 9.12 – Creating a SwiftUI app with Unit Tests enabled

Then, add the githubUsers.json file to the GithubUsersAppTests folder. You can find it in the GitHub repository at