diff --git a/tests/test_subscriber_errors.ctrl b/tests/test_subscriber_errors.ctrl
index 8309e61..403e0fa 100644
--- a/tests/test_subscriber_errors.ctrl
+++ b/tests/test_subscriber_errors.ctrl
@@ -117,3 +117,9 @@
 
 SET 51 subscriber.by-imsi-1234567890123456.msisdn hellobadmsisdn
 ERROR 51 Value failed verification.
+
+SET 52 subscriber.delete 100000
+ERROR 52 Subscriber doesn't exist.
+
+SET 53 subscriber.delete zzz
+ERROR 53 Invalid IMSI value.