diff --git a/openbsc/tests/gbproxy/gbproxy_test.c b/openbsc/tests/gbproxy/gbproxy_test.c
index df7b22e..a99986b 100644
--- a/openbsc/tests/gbproxy/gbproxy_test.c
+++ b/openbsc/tests/gbproxy/gbproxy_test.c
@@ -3331,7 +3331,7 @@
 	link_info = gbproxy_link_info_by_tlli(peer, foreign_tlli);
 	OSMO_ASSERT(link_info);
 	OSMO_ASSERT(link_info == link_info2);
-	OSMO_ASSERT(link_info->imsi_len >= 0);
+	OSMO_ASSERT(link_info->imsi_len > 0);
 	OSMO_ASSERT(!link_info->is_deregistered);
 	OSMO_ASSERT(link_info->imsi_acq_pending);