Implementing the ToDoItem struct

To be useful, to-do items need a minimal set of information. In this section, we will create a structure to hold this information while using tests to guide their development.

A to-do app needs a model class/struct to store information for to-do items:

1. We will start by adding a new test case to the unit test target. Open the to-do project that we created in the Getting started with Xcode section of Chapter 4, The App We Are Going to Build, and select the ToDoTests group.
2. Go to File | New | File..., navigate to iOS | Source | Unit Test Case Class, and click on Next. Put in the name ToDoItemTests, make it a subclass of XCTestCase, select Swift as the language, and click on Next.
3. In the next window, click on Create.
4. Now, delete the ToDoTests.swift template test case.

Adding a title property

A to-do item needs a title. Follow these steps to add one to our ToDoItem struct:

1. Open ToDoItemTests.swift and add the following...