anchor.diff:                    , {protocol, Protocol}
                     , {port, Port}
                     ],
  -  katt_util:merge_proplists(DefaultParams, Params).
  +  katt_util:merge_proplists(DefaultParams, ScenarioParams).
   
   run_scenario(Scenario, Blueprint, Params) ->
     Result = run_operations( Scenario
  
positive.code:   Request          = make_request(Req, Params),
    ExpectedResponse = make_response(Rsp),
    ActualResponse   = request(Request),
    case Result = validate(ExpectedResponse, ActualResponse) of
      pass -> run_operations( Scenario
                            , T
                            , Params
                            , [{Request, Result}|Acc]
                            );
      _    -> dbg( Scenario
                 , Description
                 , Request
                 , ExpectedResponse
                 , ActualResponse
                 , Result
                 ),
              [{Request, Result}|Acc]
    end;
  run_operations(_, [], _, Acc) ->
    Acc.
  
negative.code:   Params = make_params(Params0),
    ets:insert(?TABLE, Params),
    spawn_link(?MODULE, run, [self(), Scenario, Params]),
    receive {done, Result}    -> Result
    after   ?SCENARIO_TIMEOUT -> {error, timeout}
    end.
  
  %%%_* Internal export --------------------------------------------------
  %% @private
  run(From, Scenario, ScenarioParams) ->
    {ok, Blueprint} = katt_blueprint_parse:file(Scenario),
    Params = make_params(ScenarioParams),
    Result = run_scenario(Scenario, Blueprint, Params),
    From ! {done, Result}.
  
  %%%_* Internal =========================================================
  
  %% Take default params, and also merge in optional params from Params, to return
  %% a proplist of params.
  make_params(ScenarioParams) ->
    Protocol = proplists:get_value(protocol, ScenarioParams, "http:"),
    Port = case Protocol of
             "http:"  -> 80;
             "https:" -> 443
  