anchor.diff:      stop_counter(CounterPid),
       %% then
       ?assertReceivedMatch(
  -        {counterOnComplete, {ok, RequestsNum}, {erros, 0}}, ?TIMEOUT).
  -
  -%% TODO...
  +        {counterOnComplete, {ok, RequestsNum}, {errors, 0}}, ?TIMEOUT).
  +
   many_requests_to_one_file(Config) ->
       %% test sending many requests to one file
       %% requested blocks of file are intersected
  
positive.code: 
      fetch_many(Refs, Worker1, notify_fun(), on_complete_fun(CounterPid)),
  
      timer:sleep(?TIMEOUT),
      stop_counter(CounterPid),
      %% then
      ?assertReceivedMatch(
          {counterOnComplete, {ok, RequestsNum}, {erros, 0}}, ?TIMEOUT).
  
  error_open_fun_test(Config) ->
      %% test with open_fun callback returning an error
  
negative.code:     %% then
      ?assertReceivedMatch({on_complete, {error, canceled}}, ?TIMEOUT).
  
  many_requests_test(Config) ->
      %% test fetching many files
      [Worker1, Worker2 | _] = ?config(op_worker_nodes, Config),
  