anchor.diff:  run(Scenario, Params, Options) ->
     ScenarioTimeout = proplists:get_value( scenario_timeout
                                          , Options
  -                                       , ?SCENARIO_TIMEOUT
  +                                       , ?DEFAULT_SCENARIO_TIMEOUT
                                          ),
     spawn_link(?MODULE, run, [self(), Scenario, Params, Options]),
     receive {done, Result}    -> Result
  
positive.code: %% 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
           end,
    DefaultParams = [ {hostname, "localhost"}
                    , {protocol, Protocol}
  
negative.code: 
  make_options(Options) ->
    katt_util:merge_proplists([ {parser, fun maybe_parse_body/2}
                              , {scenario_timeout, ?DEFAULT_SCENARIO_TIMEOUT}
                              , {request_timeout, ?DEFAULT_REQUEST_TIMEOUT}
                              ]
                              , Options
                              ).
  