has anyone figured out how to test a view controller subclass implemented in kotlin MPP?

# multiplatform

[Kris Wong]

has anyone figured out how to test a view controller subclass implemented in kotlin MPP?

[Kris Wong]

hot damn... calling view on the view controller will load the view and run viewDidLoad

[Sam]

Calling view will run through the following sequence.
1. loadViewIfNecessary()
2. loadView()
3. viewDidLoad()
The best place to customize your view controller's view hierarchy is in loadView(). Be sure to call super first. Any configuration of the views should happen in viewDidLoad(). Note that your vc isn't actually attached to another view controller or window at this point so definitive size information is not available. Size customizations should be done in UIContentContainer overrides.

[Sam]

P.S. There is also a viewIfLoaded nullable property if you want the view but don't want to trigger loading. It is available in iOS 9.0+

[Kris Wong]

thanks. all that is working great. now just trying to get an event callback to be triggered for a UISwitch. it's proving much trickier.

[Kris Wong]

wow, this is frustrating. normal event dispatch through UIApplication does not work from a test. trying to call the selector directly using performSelector throws an error stating the selector is unrecognized, but I know it's valid, and it works fine just running the app.

[Sam]

If you’re trying to test UI behavior, you need to do it within the context of a running app being driven by ui tests. It’s nearly impossible to synthesize touch events in iOS. Have a look at this article for a start. https://medium.com/@johnsundell/getting-started-with-xcode-ui-testing-in-swift-ac7b1f5101e5

[Kris Wong]

will check that out. i guess the question is whether it's possible in Kotlin.

[Sam]

They can be written in ObjC so maybe. https://stackoverflow.com/questions/40968036/ios-how-to-implement-tap-on-a-button-on-xcuitest-for-objective-c

[Kris Wong]

got it. so XCUIApplication is the key

[Kris Wong]

makes sense because the call to UIApplication for the action is where it seemed to die

[Kris Wong]

looks like there are no binding for the unit testing APIs

[Kris Wong]

I didn't even check but I bet UIApplication.sharedApplication was null

[Kris Wong]

so what I observed is, there is a UIApplication instance (so a 2nd can't be created), but UIApplication.sharedApplication is null (UIApplicationMain wasn't run, and can't be run)

[Kris Wong]

so I can dispatch to the main queue, but control actions are a no-op