Xamarin UITest "Unable to set fake location on iOS Simulator" - ios

Question

I am testing a Xamarin Forms app on Android and iOS using Xamarin.UITest. Since the application depends on the GPS location, I need to set a fake location. I do this using
App.Device.SetLocation(latitude, longitude)
...where latitude and longitude are variables of type double which contain the desired coordinates.
This works fine on Android but fails on the iPhone Simulator with the following exception:
SetUp : Xamarin.UITest.XDB.Exceptions.DeviceAgentException : Unable to set location
ExitCode: 4
-d,--device-id <device-identifier> iOS Simulator GUID or 40-digit physical device ID
set-location <latitude,longitude>
Expected lat,lng: Got 48,135831,11,573423
I did some research and found a thread on the Xamarin Forums which says that it might help to round the fake coordinates to only 4 digits after the decimal point but it didn't help. Apart from that, I tried to hardcode the coordinates and to use floats instead of doubles but neither of the attempts worked.
What's going on there and how can it be fixed?
Here's my setup:
Xamarin.UITest version 2.2.4
iOS Simulator running iOS 9.3 on an iPhone 6
Host computer: Mac mini running MacOS High Sierra 10.13.6
The same issue occurred several months ago with the following setup:
Xamarin.UITest version 2.2.1
iOS Simulator running iOS 11.2 on an iPhone X
Host computer: Mac Mini running MacOS High Sierra (10.13.3)
At the time, I just left it alone, but now is the time where I need a fix.

Answer 1

Expected lat,lng: Got 48,135831,11,573423
It appears to be a bug in that Xamarin is using your local locale to convert those doubles to strings when they send them to simctl (and simctl is expecting decimal point-based strings or quoted decimals and thus it is parsing those are 4 separate numbers).
In your test code before setting the location, change the culture to en-US and set it back later to your actual culture if needed.
Something like this should work:
var currentCulture = CultureInfo.DefaultThreadCurrentCulture;
CultureInfo.DefaultThreadCurrentCulture = new System.Globalization.CultureInfo("en-US");"
// do some location setting / testing
CultureInfo.DefaultThreadCurrentCulture = currentCulture;