Connecting parts
We will now put the different parts together and implement transitions between them. We need tests for the initial view that is shown after the app is started and for the navigation from this view to the other two views. The tests have to ensure that the view controllers are passed the data they need to populate their UIs.
The initial View Controller
When you build and run the app now on the simulator, you only see a black screen. The reason for that is we haven't specified which screen the app should show after it is started. Let's write a test for this. Because this is a test about the storyboard, add an iOS | Source | Unit Test Case Class to the test target, and call it StoryboardTests. Import the main module using the @testable keyword and remove the two template tests.
Add the following test to StoryboardTests:
func testInitialViewController_IsItemListViewController() {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let navigationController = storyboard...
