CODEWITHSUNDEEP
iosswiftunit-testingxctestxctestcase
ramnik
ramnik

Reputation: 417

Why is UIView nil after manually instantiating it into mock UIViewController?

I am testing my UiViewControllers with XCUnitTests.

Sometimes I have to mock the UIViewController in order to capture a method call. For example whether performSegue has been called.

Sometimes one of the methods I test (like viewDidLoad) access an IBOutlet. When I create a custom mock subclass and then say mockViewController.textfield = UITextField() everything works great.

However, when I want to manually instantiate a UIView or a UIStackView the variable is still nil, even though the initializer of a UIView can never return nil. Why?

Maybe this has something to do with UIViews and UIStackViews to not have an intrinsic content size? How do I fix this?

Upvotes: 0

Views: 402

Answers (1)

ramnik
ramnik

Reputation: 417

Just after posting this question I already found the answer.

The reason why my manually instantiated view disappears is that my @IBOutlet is a weak var. Weak simply means, that the variable itself can not keep the instance alive. You need some other variable to keep the instance alive. In my case instead of doing

mockViewController.stackView = UIStackView()

I do

let stackView = UIStackView() mockViewController.stackView = stackView

This way the variable stackView can keep the instance alive.

Upvotes: 1

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