sgsn: add test for attach_second_attempt

Do an attach direct after an attach succeeded.
Relates: OS#2958

Change-Id: I767c3e3b0af6e7c6a1f9436fd17e2f515b0bbd05
diff --git a/sgsn/SGSN_Tests.ttcn b/sgsn/SGSN_Tests.ttcn
index bccee7f..adf87f2 100644
--- a/sgsn/SGSN_Tests.ttcn
+++ b/sgsn/SGSN_Tests.ttcn
@@ -1228,6 +1228,24 @@
 	vc_conn.done;
 }
 
+/* ATTACH + ATTACH (2nd) */
+private function f_TC_attach_forget_tlli_attach(charstring id) runs on BSSGP_ConnHdlr {
+	g_pars.t_guard  := 5.0;
+
+	/* first perform regular attach */
+	f_TC_attach(id);
+
+	/* second to perform regular attach */
+	f_TC_attach(id);
+}
+
+
+testcase TC_attach_second_attempt() runs on test_CT {
+	var BSSGP_ConnHdlr vc_conn;
+	f_init();
+	vc_conn := f_start_handler(refers(f_TC_attach_forget_tlli_attach), testcasename(), g_gb[0], 22);
+	vc_conn.done;
+}
 
 
 control {
@@ -1255,6 +1273,7 @@
 	execute( TC_attach_pdp_act_ggsn_reject() );
 	execute( TC_attach_pdp_act_user_deact_mo() );
 	execute( TC_attach_pdp_act_user_deact_mt() );
+	execute( TC_attach_second_attempt() );
 }