anchor.diff:        fileSystem: fileSystem,
         logger: logger,
         appFilenamePattern: RegExp(r'lib.*app\.so'),
  -      flutterUsage: MockUsage(),
  +      flutterUsage: TestUsage(),
       );
   
       final Archive archive = Archive()
  
positive.code:     expect(result['precompiler-trace'], <String, Object>{});
    });
  }
  
  class MockUsage extends Mock implements Usage {}
  
negative.code:       fileSystem: fileSystem,
        logger: logger,
        appFilenamePattern: RegExp(r'lib.*app\.so'),
        flutterUsage: TestUsage(),
      );
  
      final Directory outputDirectory = fileSystem.directory('example/out/foo.app')
  