anchor.diff:  
   count_answers(Num, Exp) ->
       Ans = receive
  -              #worker_answer{id = Num, response = Response} -> Response
  +              #worker_answer{id = Num, response = Response} ->
  +                  ct:print("xxx ~p", [Response]),
  +                  Response
             after ?REQUEST_TIMEOUT ->
  +              ct:print("yyy ~p", [timeout]),
                 {error, timeout}
             end,
       ?assertEqual(pong, Ans),
  
positive.code:     case spawn_and_check(Fun, Num - 1) of
          ok ->
              receive
                  ok -> ok
              after ?REQUEST_TIMEOUT ->
                  {error, timeout}
              end;
          E ->
              E
      end.
  
  
negative.code: 
  spawn_and_check(Fun, Num) ->
      Master = self(),
      ct:print("aaa ~p", [Master]),
      spawn_link(fun() ->
          Fun(),
          Master ! ok
  