Implementing ItemListDataProvider

In the previous section, we created a class to act as the data source and delegate for the item list table view. In this section, we will implement its properties and methods. But we first need a test case class for ItemListDataProvider.

Conducting the first tests

Open Project Navigator and select the ToDoTests group. Add a new Unit Test Case Class, call it ItemListDataProviderTests, and choose the Controller folder as the location to store the file. Add the @testable import ToDo import statement and remove the two test template methods.

The table view should have two sections: one for unchecked to-do items and the other for checked items. Add the following test to ItemListDataProviderTests:

func testNumberOfSections_IsTwo() {
    let sut = ItemListDataProvider()
    
    let tableView = UITableView()
    tableView.dataSource = sut
    
    let numberOfSections = tableView.numberOfSections
    XCTAssertEqual(numberOfSections, 2)
}

First, we create an instance...