XCUIApplication: How to set a custom core location

In Xcode 7 Apple added XCUITest as the new and preferred way to test the UI of your application.

I want to migrate my old testing script, but haven't found any information on how to set a custom core location when using XCUITest.

Old call:

UIATarget.localTarget().setLocation({latitude: '48.21048', longitude: '16.3595'});

I also tried to find some information on how to provide a GPX-File as a workaround via launch arguments, but had no success and idea if this is possible and what the key would be.

Does anyone know how to set a custom core location using XCUITest?