anchor.diff:    });
   
     group('screenshot', () {
  -    MockProcessManager mockProcessManager;
  -
  -    setUp(() {
  -      mockProcessManager = MockProcessManager();
  -    });
  -
  -    test('is supported on posix platforms', () {
  +    testUsingContext('is supported on posix platforms', () {
         final FuchsiaDevice device = FuchsiaDevice('id', name: 'tester');
         expect(device.supportsScreenshot, true);
  -    }, testOn: 'posix');
  +    }, overrides: <Type, Generator>{
  +      Platform: () => FakePlatform(
  +        operatingSystem: 'linux',
  +      ),
  +    });
   
       testUsingContext('is not supported on Windows', () {
         final FuchsiaDevice device = FuchsiaDevice('id', name: 'tester');
  +
         expect(device.supportsScreenshot, false);
       }, overrides: <Type, Generator>{
         Platform: () => FakePlatform(
  
positive.code:         contains('Failed to delete screenshot.ppm from the device:\n<error-message>'),
        );
      }, overrides: <Type, Generator>{
        ProcessManager: () => mockProcessManager,
        Platform: () => FakePlatform(
          environment: <String, String>{
            'FUCHSIA_SSH_CONFIG': '/fuchsia/out/default/.ssh',
  
negative.code:         environment: anyNamed('environment'),
        )).thenAnswer((_) async => ProcessResult(0, 0, '', ''));
  
        when(globals.processManager.run(
          const <String>[
            'scp',
            '-F',
  