anchor.diff:  
     test('Retrieve the current position', () async {
       when(_methodChannel.invokeMethod('getPosition'))
  -      .thenReturn(new Future<Map<String, double>>.value(_mockPosition));
  -    
  +        .thenAnswer((_) async => _mockPosition);
  +
       Position position = await _geolocator.getPosition;
   
       expect(position.latitude, _mockPosition['latitude']);
  
positive.code:     expect(position.speedAccuracy, _mockPosition['speed_accuracy']);
    });
  
    group('Postion state changes', (){
      StreamController<Map<String, double>> _controller;
  
      setUp(() {
        _controller = new StreamController<Map<String,double>>();
        when(_eventChannel.receiveBroadcastStream()).thenReturn(_controller.stream);
      });
  
      tearDown((){
        _controller.close();
      });
  
  
negative.code:   MockEventChannel _eventChannel;
    Geolocator _geolocator;
  
    const Map<String, double> _mockPosition = const <String, double>{
      'latitude': 52.561270,
      'longitude': 5.639382,
      'altitude': 3000.0,
      'accuracy': 0.0,
      'heading': 0.0,
      'speed': 0.0,
      'speed_accuracy': 0.0
    };
  
    const List<Map<String, double>> _mockPositions = const [
      <String, double>{
        'latitude': 52.561270,
        'longitude': 5.639382,
        'altitude': 3000.0,
        'accuracy': 0.0,
        'heading': 0.0,
        'speed': 0.0,
        'speed_accuracy': 0.0
      },
      <String, double>{
        'latitude': 52.560919,
        'longitude': 5.639771,
        'altitude': 3000.0,
        'accuracy': 0.0,
        'heading': 0.0,
        'speed': 0.0,
        'speed_accuracy': 0.0
      },
      <String, double>{
        'latitude': 52.562143,
        'longitude': 5.641147,
        'altitude': 3000.0,
        'accuracy': 0.0,
        'heading': 0.0,
        'speed': 0.0,
        'speed_accuracy': 0.0
      },
      <String, double>{
        'latitude': 52.562454,
        'longitude': 5.640372,
        'altitude': 3000.0,
        'accuracy': 0.0,
        'heading': 0.0,
        'speed': 0.0,
        'speed_accuracy': 0.0
      },
      <String, double>{
        'latitude': 52.561242,
        'longitude': 5.639010,
        'altitude': 3000.0,
        'accuracy': 0.0,
        'heading': 0.0,
        'speed': 0.0,
        'speed_accuracy': 0.0
      }
    ];
  
  