Xcode 14.4 Sims XCUITest Get Simulator Alert Data Error - internal ObjC exception breakpoint

Question

Using Xcode 12.4 Simulator 14.4

For the alert displayed below, I have the following function in my XCUITests that I use to pull the static text displayed on the System Alert:

 _ = addUIInterruptionMonitor(withDescription: "", handler: { (alert) -> Bool in
        var data = alert.staticTexts.allElementsBoundByIndex.map {$0.label}

        ...
    })

This worked when using Xcode 11.3 Sims 13.3; however, I just upgraded Xcode and now it crashes on when running the map function and gives the following error:

error: Execution was interrupted, reason: internal ObjC exception breakpoint(-8)..The process has been returned to the state before expression evaluation.

If I put a breakpoint, I can see the following:

po alert.staticTexts.allElementsBoundByIndex.count -> returns 3
po alert.staticTexts.allElementsBoundByIndex[0].label -> returns "Allow “X” to use your location?"
po alert.staticTexts.allElementsBoundByIndex[1].label -> returns "Your location is used to find and display nearby X facilities."
po alert.staticTexts.allElementsBoundByIndex[2] -> returns StaticText, {{32.0, 12.0}, {72.5, 16.0}}, label: 'Precise: On'

However, when I run the following (or runs during my test), it fails but as you can see from above, it does have a static text element at that position:

po alert.staticTexts.allElementsBoundByIndex[2].label -> No matches found for Element at index 2 from input {(
StaticText)} error: Execution was interrupted, reason: internal ObjC exception breakpoint(-8)

If I remain in the console and rerun the same call again, it then works though:

po alert.staticTexts.allElementsBoundByIndex[2].label -> "Precise: On"

Does anyone know what causes this error or a solution for how I can handle it in my test?

Answer 1

As this alert is "outside" your application and everything works when you debug/pause execution, I have to think this is something to do with synchronization.

Do you have anything waiting for the alert to fully display? I don't usually trust the UIInterruptionHandler to do more than auto-dismiss an alert not under test.

I'm using a page object model and typically wait for new pages in the initializer using something like _ = XCUIApplication().alerts.firstMatch.waitForExistence(timeout: 2.0)

That doesn't explain why your example of calling it twice in the console works, but timing is where I'd be looking. I feel that's the only time I ever see errors like this.

It could also be related to the map not being static or loading slowly and therefore changing the accessibility after XCUITest thinks it has finished loading and proceeds. Throwing in a nice long Thread.sleep would be the easiest way to debug that.