anchor.diff:  
   find_param_test() ->
       ?assertEqual({value, "11212"},
  -                 find_param("-p", ["-E", "engines/default_engine.so",
  +                 find_param("-p", ["-E", "foo",
                                      "-p", "11212"])),
       ?assertEqual({value, "11212"},
                    find_param("-p", ["-p", "11212",
  -                                   "-E", "engines/default_engine.so"])),
  +                                   "-E", "foo"])),
       ?assertEqual({value, "11212"},
                    find_param("-p", ["-p", "11212"])),
       ?assertEqual(false,
                    find_param("-p", ["-p"])),
       ok.
  +
  +set_param_test() ->
  +    ?assertEqual(["-E", "foo", "-p", "11212"],
  +                 set_param("-p", ["-E", "foo"],
  +                           "11212")),
  +    ?assertEqual(["-p", "11212"],
  +                 set_param("-p", [],
  +                           "11212")),
  +    ?assertEqual(["-p", "11212", "-E", "foo"],
  +                 set_param("-p", ["-p", "11211",
  +                                  "-E", "foo"],
  +                           "11212")),
  +    ?assertEqual(["-a", "hello", "-p", "11212", "-E", "foo"],
  +                 set_param("-p", ["-a", "hello",
  +                                  "-p", "11211",
  +                                  "-E", "foo"],
  +                           "11212")),
  +    ok.
  
positive.code:         Tuple -> Tuple
      end.
  
  get_port_server_param(Config, PortServerName, ParameterName) ->
      get_port_server_param(Config, PortServerName, ParameterName, node()).
  
  get_port_server_param(Config, PortServerName, ParameterName, Node) ->
      StartArgs =
          case ns_port_server:get_port_server_config(Config,
                                                     PortServerName,
                                                     Node) of
              undefined -> [];
              {PortServerName, _Path, S}       -> S;
              {PortServerName, _Path, S, _Env} -> S
          end,
      ns_port_server:find_param(ParameterName, StartArgs).
  
  find_param(_, [])              -> false;
  find_param(_, [_])             -> false;
  find_param(X, [X, Val | _])    -> {value, Val};
  find_param(X, [_, Val | Rest]) -> find_param(X, [Val | Rest]).
  
  % ----------------------------------------------
  
  
negative.code:          get_port_server_config/3,
           get_port_server_param/3,
           get_port_server_param/4,
           set_port_server_config/3,
           set_port_server_param/4,
           set_port_server_param/5,
           find_param/2,
           set_param/3]).
  
  %% gen_server callbacks
  -export([init/1,
  