diff --git a/hlr/GSUP_Test.ttcn b/hlr/GSUP_Test.ttcn
new file mode 100644
index 0000000..1118369
--- /dev/null
+++ b/hlr/GSUP_Test.ttcn
@@ -0,0 +1,54 @@
+module GSUP_Test {
+
+import from GSUP_Types all;
+import from IPA_Emulation all;
+
+type component test_CT {
+	var IPA_Emulation_CT vc_IPA;
+	var IPA_CCM_Parameters ccm_pars;
+	port IPA_GSUP_PT GSUP;
+};
+
+modulepar {
+	charstring mp_hlr_ip := "127.0.0.1";
+	integer mp_hlr_gsup_port := 4222;
+	integer mp_hlr_ctrl_port := 4259;
+};
+
+function f_init() runs on test_CT {
+	ccm_pars := c_IPA_default_ccm_pars;
+	ccm_pars.name := "Osmocom TTCN-3 GSUP Simulator";
+
+	vc_IPA := IPA_Emulation_CT.create("IPA");
+	map(vc_IPA:IPA_PORT, system:IPA_CODEC_PT);
+	connect(vc_IPA:IPA_GSUP_PORT, self:GSUP);
+	vc_IPA.start(IPA_Emulation.main_client(mp_hlr_ip, mp_hlr_gsup_port, "", -1, ccm_pars));
+}
+
+testcase TC_gsup_sai_err_invalid_imsi() runs on test_CT {
+	var hexstring imsi;
+	timer T := 10.0;
+
+	f_init();
+
+	imsi := '01234'H;
+	GSUP.send(valueof(ts_GSUP_SAI_REQ(imsi)));
+	T.start;
+	alt {
+		[] GSUP.receive(tr_GSUP_SAI_ERR(imsi, 17)) {
+			setverdict(pass);
+		}
+		[] GSUP.receive(tr_GSUP_SAI_RES(imsi)) {
+			setverdict(fail);
+		}
+		[] T.timeout {
+			setverdict(inconc);
+		}
+	}
+}
+
+control {
+	execute( TC_gsup_sai_err_invalid_imsi() );
+};
+
+};