anchor.diff:        expect(message.message, startsWith('Flutter extension can be installed from'));
         expect(message.contextUrl, 'https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter');
         expect(message.isError, false);
  -    }, overrides: noColorTerminalOverride);
  +    });
   
       group('device validator', () {
         testWithoutContext('no devices', () async {
  -        final MockDeviceManager mockDeviceManager = MockDeviceManager();
  -
  -        when(mockDeviceManager.getAllConnectedDevices()).thenAnswer(
  -          (Invocation invocation) => Future<List<Device>>.value(<Device>[])
  -        );
  -        when(mockDeviceManager.getDeviceDiagnostics()).thenAnswer(
  -          (Invocation invocation) => Future<List<String>>.value(<String>[])
  -        );
  -
  +        final FakeDeviceManager deviceManager = FakeDeviceManager();
           final DeviceValidator deviceValidator = DeviceValidator(
  -          deviceManager: mockDeviceManager,
  +          deviceManager: deviceManager,
             userMessages: UserMessages(),
           );
           final ValidationResult result = await deviceValidator.validate();
  
positive.code:               '\n'
                '! Doctor found issues in 1 category.\n'
        ));
      }, overrides: noColorTerminalOverride);
  
      testUsingContext('validate non-verbose output format for a passing run', () async {
        expect(await FakePassingDoctor(logger).diagnose(verbose: false), isTrue);
  
negative.code:               '\n'
                '! Doctor found issues in 1 category.\n'
        ));
      });
  
      testUsingContext('validate verbose output format contains trace for run with crash', () async {
        expect(await FakeCrashingDoctor(logger).diagnose(verbose: true), isFalse);
        expect(logger.statusText, contains('#0      CrashingValidator.validate'));
      });
  
  
      testUsingContext('validate non-verbose output format for run with an async crash', () async {
  