anchor.diff:                        begin
                             {H,{_F,S},Res} = run_commands(?MODULE, Cmds),
                             Cleanup(S#qcst.s, sets:to_list(S#qcst.olds)),
  -                          ?WHENFAIL(io:format("History\n~p\nState\n~p\nResult: ~p\n", [H,S,Res]),
  -                                    Res == ok)
  +                          ?WHENFAIL(
  +                             begin
  +                                 io:format("History: ~p\n", [H]),
  +                                 io:format("BE Config: ~p\nBE State: ~p\nD: ~p\n",
  +                                           [S#qcst.c, S#qcst.s, orddict:to_list(S#qcst.d)]),
  +                                 io:format("Result: ~p\n", [Res])
  +                             end,
  +                             Res == ok)
                         end)).
   
   
  
positive.code:     lists:sort(orddict:to_list(S#qcst.d)) =:= lists:sort(R);
  postcondition(_From,_To,S,_C={call,_M,is_empty,[_BeState]},R) ->
      R =:= (orddict:size(S#qcst.d) =:= 0);
  postcondition(_From,_To,_S,_C,_R) ->
      true.
  
  
  
  init_backend(Backend, Config) ->
  
negative.code:      {history, {call,Backend,list,[S#qcst.s]}},
       {history, {call,?MODULE,fold,[Backend,S#qcst.s]}},
       {history, {call,Backend,is_empty,[S#qcst.s]}},
       {history, {call,Backend,list_bucket,[S#qcst.s,bucket()]}},
       {{stopped, Backend, Volatile}, {call,Backend,drop,[S#qcst.s]}},
       {{stopped, Backend, Volatile}, {call,Backend,stop,[S#qcst.s]}}
      ].
  