Flutter/Dart : Unit test with GeoLocator

I am writing unit tests for a class that handles location services.

A simple method in my class looks like this :

  static requestPermissions() async {
    // geo locator permission
    LocationPermission geoPermission = await Geolocator.checkPermission();
    if (geoPermission == LocationPermission.denied ||
        geoPermission == LocationPermission.deniedForever) {
      //LocationPermission permission = await Geolocator.requestPermission();
    }
  }

how can i write a test for this function.