XCUI Tests with SceneKit

I started writing UI tests for my upcoming dungeon crawler game. My game engine uses SceneKit for the 3D world and XCUI  tests for the UI test automation.

I recommend this tutorial as introduction in ui test automation with XCUI.

I write this tutorial because there is not much information avilable about the combination of SCNKit and XCUI. Hopefully it helps to avoid some of the pitfalls.

The specific problem I had to solve, was to automate a scenario, where two or more interactive SCNNodes  are visible on a screen. Every node should trigger a different action.

Using screen coordinates to trigger a specific node, would have been one option, but this causes a huge overhead. My game runs on iPads and iPhones in Landscape and Portrait format. That means for each combination of screen resolution and orientation I would need different sets of coordinates.

Here is a much better solution:

I subclassed SCNNode and implemented the UIAccessibilityIdentification delegate. Every time I created an instance of MyNode  I gave it a unique accessibilityIdentifier.

class MyNode: SCNNode, UIAccessibilityIdentification {
    var accessibilityIdentifier: String?
}

Now these nodes can be addressed inside of the test code with:

app.otherElements[id].firstMatch

My first try was to get the element and call the tap method directly on the node:

app.otherElements[id].firstMatch.tap()

Unfortunately that didn’t work. An SCNNode doesn’t react on the tap method in XCUI.

The trick was to find the SCNNode , get the coordinates of the node and call tap on these coordinates:

app.otherElements[id].firstMatch.coordinate(withNormalizedOffset: CGVector.zero).tap()

And here is a  video with the automated result. The left button closes the pit and the right opens the door.

That all for today,

Cheers Stefan