anchor.diff:              get_recv(Sock, RecvCallback)
       end.
   
  -%% @doc send an iolist and receive a single line back.
  +%% @doc Send an iolist and receive a single line back.
   send_recv(Sock, IoList) ->
       send_recv(Sock, IoList, undefined).
   
  
positive.code:     (fun () ->
          {ok, RB} = cmd(version, Sock, nil, nil),
          R = binary_to_list(RB),
          ?assert(starts_with(R, "VERSION ")),
          ?assert(ends_with(R, "\r\n"))
      end)(),
  
      ok = gen_tcp:close(Sock).
  
negative.code: 
      (fun () ->
          {ok, RB} = send_recv(Sock, "not-a-command-srt\r\n", nil),
          ?assertMatch(RB, <<"ERROR">>)
      end)(),
  
      (fun () ->
          {ok, RB} = send_recv(Sock, "get not-a-key-srt\r\n", nil),
          ?assertMatch(RB, <<"END">>)
      end)(),
  
      ok = gen_tcp:close(Sock).
  