anchor.diff:    /// produces the [expected] output.
     Future<void> _checkSingleFileChanges(String content, String expected) async {
       var sourcePath = convertPath('/home/test/lib/test.dart');
  -    _checkMultipleFileChanges({sourcePath: content}, {sourcePath: expected});
  +    await _checkMultipleFileChanges(
  +        {sourcePath: content}, {sourcePath: expected});
     }
   }
   
  
positive.code: f(int i) => null; // TODO(danrubel): suggest type
  int? g(int i) => f(i);
  ''';
      _checkSingleFileChanges(content, expected);
    }
  
    test_discard_simple_condition() async {
  
negative.code:   return i + j!;
  }
  ''';
      await _checkSingleFileChanges(content, expected);
    }
  
    test_single_file_multiple_changes() async {
  