Book Image

Test-Driven iOS Development with Swift - Fourth Edition

By : Dr. Dominik Hauser
5 (1)
Book Image

Test-Driven iOS Development with Swift - Fourth Edition

5 (1)
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

Using ViewInspector to test a simple view

The view we are going to build will be used to add new to-do items to the list of items. This means it needs input fields for all information a to-do item can hold. So, let's look into that aspect in the next subsections.

Adding a title text field

As always, we start with the test. Follow these steps to add a text field for the title of a to-do item to the input view:

  1. Select the ToDoTests group in the project navigator and add a Unit Test Case Class with the name ToDoItemInputViewTests. Remove the two template test methods.
  2. Import the ViewInspector library and the main target (ToDo) so that it is testable (@testable):
    // ToDoItemInputViewTests.swift
    import XCTest
    @testable import ToDo
    import ViewInspector
  3. Before we can write tests for a SwiftUI view, we first need to extend it with the Inspectable protocol from the ViewInspector library. Add the following line right above the test case class:
    // ToDoItemInputViewTests...