anchor.diff:  
   
   %% @private
  --spec ls(node(), file_id:file_guid()) -> [file_id:file_guid()].
  +-spec ls(node(), file_id:file_guid()) -> [file_id:file_guid()] | {error, term()}.
   ls(Node, DirGuid) ->
  -    {ok, Children} = ?assertMatch(
  -        {ok, _}, lfm_proxy:get_children(Node, ?ROOT_SESS_ID, {guid, DirGuid}, 0, 10000), ?ATTEMPTS
  -    ),
  -    lists:sort(lists:map(fun({Guid, _Name}) -> Guid end, Children)).
  +    case lfm_proxy:get_children(Node, ?ROOT_SESS_ID, {guid, DirGuid}, 0, 10000) of
  +        {ok, Children} ->
  +            lists:sort(lists:map(fun({Guid, _Name}) -> Guid end, Children));
  +        {error, _} = Error ->
  +            Error
  +    end.
   
   
   update_file_content_test(Config) ->
  
positive.code:     fun
          (expected_failure, #api_test_ctx{node = TestNode}) ->
              ExpFilesInDir = api_test_memory:get(MemRef, files),
              ?assertEqual(ExpFilesInDir, ls(TestNode, DirGuid)),
              true;
          (expected_success, #api_test_ctx{node = TestNode, data = Data}) ->
              case api_test_memory:get(MemRef, success) of
  
negative.code:                     OtherFilesInDir = api_test_memory:get(MemRef, files),
                      AllFilesInDir = lists:sort([FileGuid | OtherFilesInDir]),
  
                      ?assertEqual(AllFilesInDir, ls(TestNode, DirGuid), ?ATTEMPTS),
                      api_test_memory:set(MemRef, files, AllFilesInDir),
  
                      ExpName = api_test_memory:get(MemRef, name),
  