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([sadd/1, scard/1, sdiff/1]).
  +-export([sadd/1, scard/1, sdiff/1, sdiffstore/1]).
   
   %% ====================================================================
   %% External functions
  
positive.code: 
  -spec init_per_round(atom(), [binary()]) -> ok.
  init_per_round(scard, Keys) -> sadd(Keys), ok;
  init_per_round(sdiff, Keys) ->
    edis_db:run(
      edis_db:process(0),
      #edis_command{cmd = <<"SADD">>,
  
negative.code: sdiff(_Keys) ->
    catch edis_db:run(
      edis_db:process(0),
      #edis_command{cmd = <<"SDIFF">>, args = [?KEY, ?KEY2], group = sets, result_type = multi_bulk}).
  
  -spec sdiffstore([binary()]) -> [binary()].
  sdiffstore(_Keys) ->
    catch edis_db:run(
      edis_db:process(0),
      #edis_command{cmd = <<"SDIFFSTORE">>, args = [?KEY, ?KEY, ?KEY2],
                    group = sets, result_type = multi_bulk}).