anchor.diff:  -export([all/0,
            init/0, init_per_testcase/1, init_per_round/2,
            quit/0, quit_per_testcase/1, quit_per_round/2]).
  --export([hdel/1, hexists/1, hget/1, hgetall/1, hincrby/1]).
  +-export([hdel/1, hexists/1, hget/1, hgetall/1, hincrby/1, hkeys/1]).
   
   %% ====================================================================
   %% External functions
  
positive.code:     edis_db:process(0),
      #edis_command{cmd = <<"HINCRBY">>, args = [?KEY, ?KEY, length(Keys)],
                    group = hashes, result_type = number}).
  
negative.code:                       args = [?KEY, ?KEY, edis_util:integer_to_binary(length(Keys))],
                        result_type = boolean, group = hashes}),
    ok;
  init_per_round(Fun, Keys) when Fun =:= hgetall;
                                 Fun =:= hkeys ->
    _ =
      edis_db:run(
        edis_db:process(0),
  