anchor.diff:            return (matchingEntries.first as ReadableDescriptor).read();
           } else {
             return (matchingEntries.first as LoadableDescriptor)
  -              .load(_path.joinAll(remainingPath));
  +              .load(path.posix.joinAll(remainingPath));
           }
         }
       }));
  
positive.code: 
    Stream<List<int>> load(String pathToLoad) {
      return futureStream(new Future.value().then((_) {
        if (_path.isAbsolute(pathToLoad)) {
          throw new ArgumentError("Can't load absolute path '$pathToLoad'.");
        }
  
        var split = _path.split(_path.normalize(pathToLoad));
        if (split.isEmpty || split.first == '.' || split.first == '..') {
          throw new ArgumentError("Can't load '$pathToLoad' from within "
              "'$name'.");
  
negative.code: import '../../descriptor.dart';
  import '../../scheduled_test.dart';
  import '../utils.dart';
  
  /// A descriptor describing a directory containing multiple files.
  class DirectoryDescriptor extends Descriptor implements LoadableDescriptor {
  