S1AP_Emulation: Allow retrieving {MME,ENB}_UE_ID from UeContextReleaseCmd

It's not true that it can contain several IDs. The only difference is
that it has a choice IE which can hold a pair containing both MME/ENB UE
IDs, or only MME_UE_ID.

Change-Id: I4fb51f3f50fa10400184b65d272530ea26a2bc8e
---
M library/S1AP_Emulation.ttcn
1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/library/S1AP_Emulation.ttcn b/library/S1AP_Emulation.ttcn
index 9f36225..401a26e 100644
--- a/library/S1AP_Emulation.ttcn
+++ b/library/S1AP_Emulation.ttcn
@@ -699,7 +699,13 @@
 		case (tr_S1AP_UeContextReleaseReq) {
 			return im.value_.UEContextReleaseRequest.protocolIEs[1].value_.ENB_UE_S1AP_ID;
 			}
-		/* UeContextReleaseCmd needs special handling; it can contain any number of MME/UE IDs */
+		case (tr_S1AP_UeContextReleaseCmd) {
+			if (ispresent(im.value_.uEContextReleaseCommand.protocolIEs[0].value_.uE_S1AP_IDs.uE_S1AP_ID_pair)) {
+				return im.value_.uEContextReleaseCommand.protocolIEs[0].value_.uE_S1AP_IDs.uE_S1AP_ID_pair.eNB_UE_S1AP_ID;
+			} else {
+				return omit;
+			}
+			}
 		case (tr_S1AP_ConnEstInd) {
 			return im.value_.ConnectionEstablishmentIndication.protocolIEs[1].value_.ENB_UE_S1AP_ID;
 			}
@@ -745,7 +751,13 @@
 		case (tr_S1AP_UeContextReleaseReq) {
 			return im.value_.UEContextReleaseRequest.protocolIEs[0].value_.MME_UE_S1AP_ID;
 			}
-		/* UeContextReleaseCmd needs special handling; it can contain any number of MME/UE IDs */
+		case (tr_S1AP_UeContextReleaseCmd) {
+			if (ispresent(im.value_.uEContextReleaseCommand.protocolIEs[0].value_.uE_S1AP_IDs.uE_S1AP_ID_pair)) {
+				return im.value_.uEContextReleaseCommand.protocolIEs[0].value_.uE_S1AP_IDs.uE_S1AP_ID_pair.mME_UE_S1AP_ID;
+			} else {
+				return im.value_.uEContextReleaseCommand.protocolIEs[0].value_.uE_S1AP_IDs.mME_UE_S1AP_ID;
+			}
+			}
 		case (tr_S1AP_ConnEstInd) {
 			return im.value_.ConnectionEstablishmentIndication.protocolIEs[0].value_.MME_UE_S1AP_ID;
 			}

