msc: add tests for SMS and voice call while Paging

Start a second
- MT SMS
- MT call
while a Paging is already ongoing.

The second trans being an SMS works.

The second trans being a call fails with current osmo-msc master; a fix is in
the related patch (s.b.).

Related: Idd4537b5f4817d17e5c87d9a93775a32aee0e7be
Change-Id: Ieeae6322d4e80893ea3408c6b74bf8e32bea8e46
diff --git a/msc/BSC_ConnectionHandler.ttcn b/msc/BSC_ConnectionHandler.ttcn
index 623dae9..007e541 100644
--- a/msc/BSC_ConnectionHandler.ttcn
+++ b/msc/BSC_ConnectionHandler.ttcn
@@ -1766,22 +1766,25 @@
 	f_mo_sms_wait_rp_ack(spars);
 }
 
+function f_mt_sms_deliver_pdu(in SmsParameters spars)
+runs on BSC_ConnHdlr
+return template PDU_DTAP_MT {
+	var template TPDU_RP_DATA_SGSN_MS tp_mt := tr_SMS_DELIVER(?, spars.tp.ud, spars.tp.pid, spars.tp.dcs, ?);
+	var template RPDU_SGSN_MS rp_mt := tr_RP_DATA_MT(?, spars.rp.smsc_addr, omit, tp_mt);
+	var template PDU_ML3_NW_MS l3_mt := tr_ML3_MT_SMS(?, c_TIF_ORIG, tr_CP_DATA_MT(rp_mt));
+	return tr_PDU_DTAP_MT(l3_mt, spars.dlci);
+}
+
 /* Wait for MT SMS on an already existing DTAP connection */
 function f_mt_sms_expect(inout SmsParameters spars)
 runs on BSC_ConnHdlr {
 	var template (value) PDU_ML3_MS_NW l3_mo;
-	var template TPDU_RP_DATA_SGSN_MS tp_mt;
-	var template RPDU_SGSN_MS rp_mt;
-	var template PDU_ML3_NW_MS l3_mt;
 	var PDU_DTAP_MT dtap_mt;
 
 	var default d := activate(as_other_sms());
 
 	/* Expect CP-DATA(RP-DATA(SMS-DELIVER)) */
-	tp_mt := tr_SMS_DELIVER(?, spars.tp.ud, spars.tp.pid, spars.tp.dcs, ?);
-	rp_mt := tr_RP_DATA_MT(?, spars.rp.smsc_addr, omit, tp_mt);
-	l3_mt := tr_ML3_MT_SMS(?, c_TIF_ORIG, tr_CP_DATA_MT(rp_mt));
-	BSSAP.receive(tr_PDU_DTAP_MT(l3_mt, spars.dlci)) -> value dtap_mt;
+	BSSAP.receive(f_mt_sms_deliver_pdu(spars)) -> value dtap_mt;
 
 	/* Extract relevant identifiers */
 	spars.tid := bit2int(dtap_mt.dtap.tiOrSkip.transactionId.tio);