How to test if view controller is dismissed or popped - ios

Question

i want to write an unit test for my function, here is code:
func smartBack(animated: Bool = true) {
if isModal() {
self.dismiss(animated: animated, completion: nil)
} else {
self.navigationController?.popViewController(animated: animated)
}
}
This method automatically chooses dismiss or pop. So, how i can check if viewcontroller popped or dismissed after this function? Thank you for help

Answer 1

You can check the view controller's isBeingDismissed property in either its viewWillAppear or viewDidAppear function.
See https://developer.apple.com/documentation/uikit/uiviewcontroller/2097562-isbeingdismissed.

Answer 2

func smartBack(animated: Bool = true) will be:
func smartBack(animated: Bool = true) {
if self.navigationController?.viewControllers.first == self {
self.dismiss(animated: animated, completion: nil)
} else {
self.navigationController?.popViewController(animated: true)
}
}

Answer 3

You can use property self.isBeingPresented, will return true is view controller presented otherwise false if pushed.

Answer 4

You could check the viewControllers stack and see if your viewController is included or not, using:
self.navigationController.viewControllers
This will return a [UIViewController] contained in the navigationController stack.

Answer 5

Personally I would use Mocks to track when certain methods are called.
You can do this like so:
class MockNavigationController: UINavigationController {
var _popCalled: Bool = false
override func popViewController(animated: Bool) -> UIViewController? {
_popCalled = true
return self.viewControllers.first
}
}
Then anytime your code calls popViewController, the _popCalled value would be updated but it wouldn't actually pop anything. So you can assert the _popCalled value to make sure that the expected call happened.
This makes it easy to test that an expected thing happened and also prevents you running actual code in your tests. This method could easily be a service call, or db update, setting a flag etc, so can be much safer.
They can be difficult to understand at first though. I would suggest reading up on them before heavy use.
A full example in a playground:
import UIKit
import PlaygroundSupport
import MapKit
class ClassUnderTest: UIViewController {
var isModal: Bool = false
func smartBack(animated: Bool = true) {
if isModal {
self.dismiss(animated: animated, completion: nil)
} else {
self.navigationController?.popViewController(animated: animated)
}
}
}
class MockNavigationController: UINavigationController {
var _popCalled: Bool = false
override func popViewController(animated: Bool) -> UIViewController? {
_popCalled = true
return self.viewControllers.first
}
}
class MockClassUnderTest: ClassUnderTest {
var _mockNavigationController = MockNavigationController()
override var navigationController: UINavigationController? {
return _mockNavigationController
}
var _dismissCalled: Bool = false
override func dismiss(animated flag: Bool, completion: (() -> Void)? = nil) {
_dismissCalled = true
}
}
var subject = MockClassUnderTest()
subject.isModal = true
subject.smartBack();
var navigation = subject.navigationController as! MockNavigationController
print(subject._dismissCalled)
print(navigation._popCalled)
OUTPUT:
true
false
subject = MockClassUnderTest();
subject.isModal = false
subject.smartBack();
navigation = subject.navigationController as! MockNavigationController
print(subject._dismissCalled)
print(navigation._popCalled)
OUTPUT:
false
true
In this example, you are overriding the dismiss and pop methods which would be called in either case. In your unit test you would just assert the stubbed values (_popCalled) are true or false for your expectations.

Answer 6

I solved in this way. I have needed to test a simple method that contains this: dismiss(animated: true, completion: nil) and I made a temporal mock that simulates a viewController that do a push to my MainController which it is where I apply the dismissView.
func testValidatesTheDismissOfViewController() {
// Given
let mockViewController: UIViewController = UIViewController()
let navigationController = UINavigationController(rootViewController: mockViewController)
// Create instance of my controller that is going to dismiss.
let sut: HomeWireFrame = HomeWireFrame().instanceController()
navigationController.presentFullScreen(sut, animated: true)
// When
sut.loadViewIfNeeded()
sut.closeView()
// Create an expectation...
let expectation = XCTestExpectation(description: "Dismiss modal view: HomeViewController")
// ...then fulfill it asynchronously
DispatchQueue.main.async { expectation.fulfill() }
wait(for: [expectation], timeout: 1)
// Then - if its different of my home controller
XCTAssertTrue(!(navigationController.topViewController is HomeViewController))
}
I hope can help, I´m here to any doubt.

Answer 7

It is worked for me:
func smartBack(animated: Bool = true) {
if self.navigationController == nil {
self.dismiss(animated: animated, completion: nil)
} else {
self.navigationController?.popViewController(animated: true)
}
}