Feature/alert controller assertion #20

lgauthier · 2017-07-13T00:16:41Z

@nhgrif This adds an assertion for testing that a view controller presented a UIAlertController with a particular style, title, message, and actions. Just so you're aware, in order to test this assertion, I had to be able to successfully present an alert which isn't possible without a window. So, I added a new test target that actually runs an empty UIKit app so I have a window to add my presenter view controller to for the tests.

nhgrif

Going to wait on reviewing this further until you've investigated the host application / UIWindow stuff we just discussed.

lgauthier · 2017-07-13T01:38:17Z

@nhgrif I've done some testing with attempting to successfully present a view controller without using a host application target. I've tried a random assortment of things, but I haven't had any luck so far.

If we simply create a UIViewController instance and call present(_:animated:completion:) on it, the presentation fails and the following warning is printed to the console:

Warning: Attempt to present <SomeViewController: 0x7fb49ef25d20> on <SomeOtherViewController: 0x7fb49ee369d0> whose view is not in the window hierarchy!

From this warning, it's clear that we at least need to have a UIWindow instance to add our view controller to. If we instantiate our own and make our view controller the root view controller of that window, the same warning from above is printed to the console and the presentation still fails. If we attempt to make this window the key window by calling makeKey() or makeKeyAndVisible(), an exception is thrown:

caught "NSInternalInconsistencyException", "props must have a valid clientID"

This is a pretty vague error message, but my guess is that the window cannot become a key window without an application. However, without a host application target, UIApplication.shared has no value:

(lldb) po UIApplication.shared
<uninitialized>

Any attempt to initialize a UIApplication instance manually results in an exception being thrown:

caught "NSInternalInconsistencyException", "There can only be one UIApplication instance."

Adding the code below to the test target in an attempt to designate a UIApplicationDelegate for the main function the way you might normally do it in an iOS application doesn't work either. In this case, application(_:didFinishLaunchingWithOptions:) never even gets called. It seems that the @UIApplicationMain attribute is ignored. I imagine it's only recognized in an application target.

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    
    var window: UIWindow?
    
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        
        window = UIWindow(frame: UIScreen.main.bounds)
        window?.rootViewController = UIViewController()
        window?.makeKeyAndVisible()
        
        return true
    }
}

Got any other ideas for me to test out?

…dTests target.

lgauthier · 2017-07-13T20:11:53Z

@nhgrif I've removed the hosted tests target. Setting the view controller as the root view controller of the window doesn't seem to add the view controller's view to the window unless the window is the key window (and it can't be the key window without a host application). However, you can simply add the view controller's view as a subview to the window directly. As long as the view controller's view is a subview of the window, it can successfully present another view controller. So, that's what I did for the alert controller assertion tests.

coveralls · 2017-07-13T20:43:57Z