diff --git a/tests/sgsn/sgsn_test.c b/tests/sgsn/sgsn_test.c
index df4df3b..0e5267b 100644
--- a/tests/sgsn/sgsn_test.c
+++ b/tests/sgsn/sgsn_test.c
@@ -1132,7 +1132,7 @@
 {
 	/* Fake an authentication */
 	OSMO_ASSERT(mmctx->subscr);
-	mmctx->is_authenticated = 1;
+	mmctx->sec_ctx = OSMO_AUTH_TYPE_GSM;
 	gprs_subscr_update_auth_info(mmctx->subscr);
 
 	return 0;