anchor.diff:                    {route, <<"<sip:bob@biloxi.com>">>},
                     {'max-forwards', 15}],
   
  +    CancelHeaders = [{via, <<"SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKkjshdyff">>},
  +                  {to, <<"Bob <sip:bob@biloxi.com>">>},
  +                  {from, <<"Alice <sip:alice@atlanta.com>;tag=88sja8x">>},
  +                  {'call-id', <<"987asjd97y7atg">>},
  +                  {cseq, <<"986759 CANCEL">>},
  +                  {route, <<"<sip:alice@atlanta.com>">>},
  +                  {route, <<"<sip:bob@biloxi.com>">>},
  +                  {'max-forwards', 15}],
  +
       ACK = #sip_request{method = 'ACK', uri = <<"sip:bob@biloxi.com">>, headers = ACKHeaders},
  +    Cancel = #sip_request{method = 'CANCEL', uri = <<"sip:bob@biloxi.com">>, headers = CancelHeaders},
       [
  -     ?_assertEqual(parse_all_headers(ACK), parse_all_headers(create_ack(Request, Response2)))
  +     ?_assertEqual(parse_all_headers(ACK), parse_all_headers(create_ack(Request, Response2))),
  +     ?_assertEqual(parse_all_headers(Cancel), parse_all_headers(create_cancel(Request)))
        ].
   
   -spec helpers_test_() -> list().
  
positive.code:     InvalidResponse2 = create_response(ValidRequest2, 200),
      ValidResponse2 = append_header(contact, sip_headers:address(<<>>, <<"sip:alice@localhost">>, []), InvalidResponse2),
  
      % Record-Route is SIPS, so Contact must be sips
      InvalidResponse3 = ValidResponse2,
  
      [% Request validation
  
negative.code:      ?_assertEqual(ok, validate_request(ValidRequest2)),
       ?_assertEqual({error, {invalid, contact_must_be_sips}}, validate_request(InvalidRequest2)),
       ?_assertEqual(ok, validate_request(ValidRequest3)),
  
       % Response validation
       ?_assertEqual(ok, validate_response(ValidResponse)),
  