MSC/SMPP: fix RP-ACK expectations in TC_smpp_mo_sms

The MSC shall not send RP-ACK before the response from ESME.

Change-Id: Ide1376cae8e75412039b7dc9f0b8bb390eab2280
Related: OS#4351
diff --git a/msc/MSC_Tests.ttcn b/msc/MSC_Tests.ttcn
index 94fac74..ccfc154 100644
--- a/msc/MSC_Tests.ttcn
+++ b/msc/MSC_Tests.ttcn
@@ -2109,9 +2109,10 @@
 
 	/* Perform location update so IMSI is known + registered in MSC/VLR */
 	f_perform_lu();
-	f_establish_fully(EST_TYPE_MO_SMS);
 
-	f_mo_sms(spars);
+	/* MS/UE submits a MO SMS */
+	f_establish_fully(EST_TYPE_MO_SMS);
+	f_mo_sms_submit(spars);
 
 	var SMPP_PDU smpp;
 	var template SMPP_PDU tr_smpp := tr_SMPP(c_SMPP_command_id_deliver_sm, ESME_ROK);
@@ -2149,6 +2150,9 @@
 	[] SMPP.receive(tr_SMPP(c_SMPP_command_id_alert_notification, ESME_ROK)) { repeat; }
 	}
 
+	/* MSC terminates the SMS transaction with RP-ACK */
+	f_mo_sms_wait_rp_ack(spars);
+
 	f_expect_clear();
 }
 testcase TC_smpp_mo_sms() runs on MTC_CT {