anchor.diff:      {ok, ArchiveRootDirPath} = lfm_proxy:get_file_path(Node, SessionId, ArchiveRootDirGuid),
       ArchiveDataDirPath = filename:join([ArchiveRootDirPath, <<"data">>]),
       {ok, #file_attr{guid = ArchiveDataDirGuid}} = lfm_proxy:stat(Node, SessionId, {path, ArchiveDataDirPath}),
  -    {ok, [{TargetGuid, _}, _]} = lfm_proxy:get_children(Node, SessionId, ?FILE_REF(ArchiveDataDirGuid), 0, ?LISTED_CHILDREN_LIMIT),
  +    {ok, [{TargetGuid, _} | _]} = lfm_proxy:get_children(Node, SessionId, ?FILE_REF(ArchiveDataDirGuid), 0, ?LISTED_CHILDREN_LIMIT),
       assert_copied(Node, SessionId, DatasetRootFileGuid, TargetGuid).
   
   
  
positive.code: assert_structure(Node, SessionId, ArchiveId, DatasetRootFileGuid, ?ARCHIVE_PLAIN_LAYOUT) ->
      ArchiveRootDirUuid = ?ARCHIVE_DIR_UUID(ArchiveId),
      ArchiveRootDirGuid = file_id:pack_guid(ArchiveRootDirUuid, oct_background:get_space_id(?SPACE)),
      {ok, [{TargetGuid, _}, _]} = lfm_proxy:get_children(Node, SessionId, ?FILE_REF(ArchiveRootDirGuid), 0, ?LISTED_CHILDREN_LIMIT),
      assert_copied(Node, SessionId, DatasetRootFileGuid, TargetGuid);
  assert_structure(Node, SessionId, ArchiveId, DatasetRootFileGuid, ?ARCHIVE_BAGIT_LAYOUT) ->
      ArchiveRootDirUuid = ?ARCHIVE_DIR_UUID(ArchiveId),
  
negative.code: 
  assert_content_copied_internal(Node, SourceHandle, TargetHandle, Offset) ->
      BytesToRead = 10000, 
      {ok, SourceContent} = lfm_proxy:check_size_and_read(Node, SourceHandle, Offset, BytesToRead),
      ?assertEqual({ok, SourceContent},
          lfm_proxy:check_size_and_read(Node, TargetHandle, Offset, BytesToRead), ?ATTEMPTS),
      case SourceContent of
          <<>> -> ok;
          _ -> assert_content_copied_internal(Node, SourceHandle, TargetHandle, Offset + BytesToRead)
  