unit testing cell is nil - swift

Question

Issue:
I loaded collectionView with 3 Dummy items. However Cell came back nil, is it because view was never loaded? How do you guys test your collectionViewCell type?
Code
var window: UIWindow?
var sut: QuestsDataProvider!
var collectionView: UICollectionView!
override func setUp() {
super.setUp()
bulletinController = BulletinController(collectionViewLayout: UICollectionViewFlowLayout())
sut = QuestsDataProvider(acceptedQuests: false, completedQuests: false)
bulletinController.collectionView?.dataSource = sut
bulletinController.collectionView?.delegate = sut
window = UIWindow()
window?.makeKeyAndVisible()
window?.rootViewController = bulletinController
}
func testCellIsQuestCell() {
let indexPath = IndexPath(item: 1, section: 0)
let cell = collectionView.cellForItem(at: indexPath)
guard let count = sut.questManager?.quests.count else {return XCTFail()}
XCTAssertTrue(cell is QuestCell)
}
Edit:
Upon Further testing, I'm able to see the dummy Cell inside my simulator and get a accurate count from numberOfitems(InSection: Int). However I have no visible Cell.
2nd Edit:
After further research, I found out the issue is collectionView.cellForItem(at: indexPath) only shows visible cell. Is there any other method for unit testing collection view cell type?

Answer 1

You need to access the view object of the view controller before it and its subview components will be fully initialised.
You should be able to just do let _ = bulletinController.view in your setup function. it is quite a common approach, see here
Relevant parts included below
func setupCreateOrderViewController()
{
let bundle = NSBundle(forClass: self.dynamicType)
let storyboard = UIStoryboard(name: "Main", bundle: bundle)
createOrderViewController = storyboard.instantiateViewControllerWithIdentifier("CreateOrderViewController") as! CreateOrderViewController
_ = createOrderViewController.view
}
Quote from link:
But there are two very, very important things happening on the last line:
Asking for the view property of createOrderViewController causes the view to be loaded. The viewDidLoad() method is called as a result.
After the view is loaded, all the IBOutlets are also set up and ready to be used in out tests. For example, you can assert that a text field outlet’s text equal to a string you expect.
EDIT:
You can also just call loadViewIfNeeded() on the view controller, which will do the same thing.
Loads the view controller’s view if it has not yet been loaded.