How to unit test a computed property in Swift?

Asked Jun 22 '20 at 11:41

Active Jun 22 '20 at 11:41

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How can I unit test the guard statement of a computed property in swift?

When the unit tests are run, the fataError line is not included in the code coverage.

Is there any way to test the computed properties?

class HomePresenter: HomeViewToPresenterProtocol {

    var view: HomePresenterToViewProtocol?
    var router: HomePresenterToRouterProtocol?
    var interactor: HomePresentorToInterectorProtocol?

    var homeView: UIViewController {
        guard let view = view as? UIViewController else {
            fatalError("View cannot be casted as UIViewController")
        }
        return view
    }

    init(view: HomePresenterToViewProtocol, interactor: HomePresentorToInterectorProtocol, router: HomePresenterToRouterProtocol) {
        self.view = view
        self.interactor = interactor
        self.router = router
    }

}

asked Jun 22 '20 at 11:41

NkaBall

Should you really use fatalError in production code? – Joakim Danielson Jun 22 '20 at 11:45
I cannot? I thought it is a good practice to use fatalError. – NkaBall Jun 22 '20 at 11:47
Well it will crash your app, is this really what you want and do you think it will be a good user experience when the app just crashes without any message or information explaining why. – Joakim Danielson Jun 22 '20 at 11:50
yes, I know the app will crash if the runtime hits that code. But it is not likely to happen because the casting will always succeed. – NkaBall Jun 22 '20 at 11:54
Do you really need to bother with a unit test then? In generar you can always use fail, `XCTFail()`, to force the test to fail if it continues after a code row – Joakim Danielson Jun 22 '20 at 11:59
You would achieve the same effect much more easily by `return view as! UIViewController`. – Mike Taverne Jun 22 '20 at 15:30

How to unit test a computed property in Swift?

0 Answers0