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

Checking the to-do item

When the user of the app taps the Done button, our app has to tell the to-do item store to change the item's status to Done. Follow these steps to implement that feature:

  1. Add the following test method to ToDoItemDetailsViewControllerTests:
    // ToDoItemDetailsViewControllerTest.swift
    func test_sendingButtonAction_shouldCheckItem() {
      let toDoItem = ToDoItem(title: "dummy title")
      sut.toDoItem = toDoItem
      let storeMock = ToDoItemStoreProtocolMock()
      sut.toDoItemStore = storeMock

ToDoItemDetailsViewController doesn't have a property for toDoItemStore. This means we have to pause writing this test and add this property first.

  1. Go to ToDoItemDetailsViewController and add the toDoItemStore property:
    // ToDoItemDetailsViewController.swift
    var toDoItemStore: ToDoItemStoreProtocol?
  2. Now we can finish the test:
    // ToDoItemDetailsViewControllerTests.swift
    func test_sendingButtonAction_shouldCheckItem...