anchor.diff:      unregister(?MODULE),
       ok.
   
  +%% Scenario tested:
  +%% - client INVITE transaction is created
  +%% - 5xx response is received
   client_invite_err(Transport)->
       register(?MODULE, self()),
   
  
positive.code:     unregister(?MODULE),
      ok.
  
  -endif.
negative.code:     ?assertReceive("Expect ACK to be sent by tx layer",
                     {tp, _Conn, {request, Remote, ACK}}),
  
      % wait 32 seconds for unreliable transport only
      sip_transport:is_reliable(Transport) orelse timer:sleep(32000),
  
      ?assertReceive("Expect tx to terminate after receiving final response",
  