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

Presenting two sections

As we have already refactored to a diffable data source, supporting two sections in the table view is quite easy. Follow these steps to implement two sections:

  1. As always, we need to start with a failing test. Add the following test to ToDoItemsListViewControllerTests:
    // ToDoItemsListViewControllerTests.swift
    func test_numberOfSections_shouldReturnTwo() {
      var doneItem = ToDoItem(title: "dummy 2")
      doneItem.done = true
        .send([ToDoItem(title: "dummy 1"),
      let result = sut.tableView.numberOfSections
      XCTAssertEqual(result, 2)

In this test, we set a to-do item and a done item to the table view using toDoItemStoreMock. The name of the test method should also include what the preconditions of the tests are. We use a shorter name in the book because...