anchor.diff:    });
   }
   
  -class _Device extends Mock implements TestDevice {}
  +class FakeDevice extends Fake implements TestDevice {}
  
positive.code:     });
  
      testWithoutContext('handles a null parent', () {
        final _Device device = _Device();
  
        expect(() => eventPrinter.handleFinishedTest(device), returnsNormally);
        expect(() => eventPrinter.handleStartedDevice(observatoryUri), returnsNormally);
  
negative.code: 
  import 'package:flutter_tools/src/test/event_printer.dart';
  import 'package:flutter_tools/src/test/test_device.dart';
  import 'package:test/fake.dart';
  
  import '../../src/common.dart';
  
  