ViewControllerTesting

I was having a few problems with unit testing view controllers so I decided to post on SO http://stackoverflow.com/questions/28733016/view-controller-tdd

With the help of the answers, I was able to find the solutions to my problems and here are the takeaways that I got:

1. I made anything class/method/variable that I want to test public. I do not need to add the swift files to the test target.

2. I only needed to set "Defines Module" for the "Main" target (as opposed to the "Test" target or the entire project)

3. When instantiating the storyboard, the bundle should be set to nil rather than NSBundle(forClass: self.dynamicType), otherwise tests will fail.

4. As modocache stated, it is good to give your view controller's a StoryboardID and instantiate them like so:

   viewController = storyboard.instantiateViewControllerWithIdentifier("FirstViewController") as FirstViewController However, instantiating the view controller like this ONLY instantiates the view controller alone, and not any navigation controllers that it may be embedded in. That means, attempting to do

   XCTAssertFalse(viewController.navigationController!.navigationBarHidden, "Bar should show by default") will result in a nil exception. I confirmed this with

   XCTAssertNil(viewController.navigationController?, "navigation controller doesn't exist")

which resulted in a successful test.

Since I wanted to check the state of the navigation bar in FirstViewController, you must instantiate the view controller like so:

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let navigationController = storyboard.instantiateInitialViewController() as UINavigationController
viewController = navigationController.topViewController as FirstViewController

Now performing the test

XCTAssertFalse(viewController.navigationController!.navigationBarHidden, "nav bar should be showing by default")

results in a successful test.

5. let _ = viewController.view does indeed trigger viewDidLoad() which was confirmed by a test

6. let _ = viewController.view does not trigger viewWillAppear(), and I presume anything afterwards aswell. viewController.viewWillAppear(false/true) needs to be called manually to trigger it (Confirmed by a test).

Update #2

After all the above, I still could not figure out how to transition from the first view controller to the second view controller (so that I may test navigation bar properties in SecondViewControllerTests.swift). I tried

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let nc = storyboard.instantiateInitialViewController() as UINavigationController
let firstVC = nc.topViewController as FirstViewController
firstVC.performSegueWithIdentifier("FirstToSecond", sender: nil)
secondVC = nc.topViewController as SecondViewController

which caused an error.

I also tried

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let nc = storyboard.instantiateInitialViewController() as UINavigationController
let firstVC = nc.topViewController as FirstViewController
firstVC.toSecondVCButton.sendActionsForControlEvents(UIControlEvents.TouchUpInside)
secondVC = nc.topViewController as SecondViewController

which did not work.

I eventually tried

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let nc = storyboard.instantiateInitialViewController() as UINavigationController
vc = storyboard.instantiateViewControllerWithIdentifier("Second") as SecondViewController
nc.pushViewController(vc, animated: false)
let _ = vc.view
vc.viewWillAppear(false)

which worked perfectly with my tests (allowed me to access navigation bar properties)!

I have summarised these points in my blog, https://medium.com/pangers/unit-testing-view-controllers-4e025eaac400