anchor.diff:      part 'test_lib.g.dart';
       ''',
         testLibPartContent: '''
  +    part of 'test_lib.dart';
       @deprecated
       int x;
       ''',
  
positive.code: class Customer { }
  ''';
  
  const _testLibContentSyntaxError = r'''
  final int foo = 42
  ''';
  
negative.code:     );
    });
  
    test('Does not fail when there is no output', () async {
      final sources = _createPackageStub(testLibContent: 'class A {}');
      final builder =
  