diff --git a/tests/gsm0408/gsm0408_test.c b/tests/gsm0408/gsm0408_test.c
index 659a03b..af62537 100644
--- a/tests/gsm0408/gsm0408_test.c
+++ b/tests/gsm0408/gsm0408_test.c
@@ -71,6 +71,7 @@
 void rsl_data_request(void) {}
 void gsm0411_rcv_sms(void) {}
 void schedule_timer(void) {}
+void del_timer(void) {}
 void subscr_get_by_tmsi(void) {}
 void subscr_update(void) {}
 void db_subscriber_assoc_imei(void) {}