anchor.diff:  
   relay_message(Msg, Room) ->
       [Pid ! <<Msg/binary>> || Pid <- pg2:get_members(Room) -- [self()]].
  +
  +
  +%% ===================================================================
  +%% Tests
  +%% ===================================================================
  +
  +-ifdef(TEST).
  +
  +new_room_name_type_test() ->
  +    Name = new_room_name(),
  +    ?assert(is_binary(Name)).
  +
  +new_room_name_unique_test() ->
  +    Name = new_room_name(),
  +    Other = new_room_name(),
  +    ?assertNotEqual(Name, Other).
  +
  +-endif.
positive.code: 
  -record(state, {room=undefined}).
  
  %% ===================================================================
  %% Websocket API
  %% ===================================================================
  
  init({tcp, http}, Req, Opts) ->
      {upgrade, protocol, cowboy_websocket}.
  
  websocket_init(_TransportName, Req, _Opts) ->
  
negative.code:     ok.
  
  %% ===================================================================
  %% Internal functions
  %% ===================================================================
  
  new_room_name() ->
  