anchor.diff:    outputPreferences: OutputPreferences.test(wrapText: true),
   ));
   final String flutterBin = fileSystem.path.join(getFlutterRoot(), 'bin', platform.isWindows ? 'flutter.bat' : 'flutter');
  -final String dartBin = fileSystem.path.join(getFlutterRoot(), 'bin', platform.isWindows ? 'dart.bat' : 'dart');
   
   /// A test for flutter upgrade & downgrade that checks out a parallel flutter repo.
   void main() {
  
positive.code:     }
    });
  
    testWithoutContext('Can upgrade and downgrade a Flutter checkout', () async {
      final Directory testDirectory = parentDirectory.childDirectory('flutter');
      testDirectory.createSync(recursive: true);
  
  
negative.code: import 'package:flutter_tools/src/base/terminal.dart';
  
  import '../src/common.dart';
  import '../src/context.dart';
  import 'test_utils.dart';
  
  const String _kInitialVersion = 'v1.9.1';
  