anchor.diff:      ]);
       residentRunner = HotRunner(
         <FlutterDevice>[
  -        mockFlutterDevice,
  +        flutterDevice,
         ],
         stayResident: false,
         debuggingOptions: DebuggingOptions.enabled(
  
positive.code:         devtoolsHandler: createNoOpHandler,
        );
      });
      mockFlutterDevice = MockFlutterDevice();
      mockDevice = FakeDevice();
      mockDevFS = FakeDevFS();
      // FlutterDevice Mocks.
      when(mockFlutterDevice.updateDevFS(
        invalidatedFiles: anyNamed('invalidatedFiles'),
        mainUri: anyNamed('mainUri'),
        target: anyNamed('target'),
        bundle: anyNamed('bundle'),
        firstBuildTime: anyNamed('firstBuildTime'),
        bundleFirstUpload: anyNamed('bundleFirstUpload'),
        bundleDirty: anyNamed('bundleDirty'),
        fullRestart: anyNamed('fullRestart'),
        projectRootPath: anyNamed('projectRootPath'),
        pathToReload: anyNamed('pathToReload'),
        dillOutputPath: anyNamed('dillOutputPath'),
        packageConfig: anyNamed('packageConfig'),
      )).thenAnswer((Invocation invocation) async {
        return UpdateFSReport(
          success: true,
          syncedBytes: 0,
          invalidatedSourcesCount: 1,
        );
      });
      when(mockFlutterDevice.devFS).thenReturn(mockDevFS);
      when(mockFlutterDevice.device).thenReturn(mockDevice);
      when(mockFlutterDevice.stopEchoingDeviceLog()).thenAnswer((Invocation invocation) async { });
      when(mockFlutterDevice.observatoryUris).thenAnswer((_) => Stream<Uri>.value(testUri));
      when(mockFlutterDevice.connect(
        reloadSources: anyNamed('reloadSources'),
        restart: anyNamed('restart'),
        compileExpression: anyNamed('compileExpression'),
        getSkSLMethod: anyNamed('getSkSLMethod'),
        allowExistingDdsInstance: anyNamed('allowExistingDdsInstance'),
      )).thenAnswer((Invocation invocation) async { });
      when(mockFlutterDevice.setupDevFS(any, any))
        .thenAnswer((Invocation invocation) async {
          return testUri;
        });
      when(mockFlutterDevice.vmService).thenAnswer((Invocation invocation) {
        return fakeVmServiceHost?.vmService;
      });
    });
  
    testUsingContext('ResidentRunner can attach to device successfully', () => testbed.run(() async {
  
negative.code:     globals.fs.file(globals.fs.path.join('lib', 'main.dart')).createSync(recursive: true);
      residentRunner = HotRunner(
        <FlutterDevice>[
          flutterDevice,
        ],
        stayResident: false,
        debuggingOptions: DebuggingOptions.enabled(const BuildInfo(
  