Extract test helpers to make your tests more readable. They’ll also make the tests less fragile.
Tapping buttons is something we’ll do quite a bit when unit testing view controllers. But sendActions(for: .touchUpInside) isn’t very descriptive. We can improve the readability of our tests by extracting a helper to tap UIButtons.
Putting test helpers in a separate file makes it easier to find them. In the Project Navigator, select the ButtonTapTests group and press ⌘-N to make a new file. Select Swift File, name it TestHelpers.swift, and set its target to the test target. Give it the following code:
| | import UIKit |
| | |
| | func tap(_ button: UIButton) { |
| | button.sendActions(for: .touchUpInside) |
| | } |
Change the test to use this new helper:
| | tap(sut.button) |
Run the tests and confirm that the console output says Button was tapped.
UIBarButtonItems aren’t UIControls, so we can’t call sendActions(for:) on them. We can make a separate helper for them. We won’t use it until the example in Chapter 17, Unleash the Power of Refactoring, where we’ll work through an example with a UIBarButtonItem. But for reference, here’s a test helper to tap them:
| | func tap(_ button: UIBarButtonItem) { |
| | _ = button.target?.perform(button.action, with: nil) |
| | } |
Swift’s function overloading lets us support the common abstraction of tap(_:) for two types. This also means that if we change a button type from UIButton to UIBarButton, the test code can stay the same.
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Extract test helpers to make your tests more readable. They’ll also make the tests less fragile. |