diff --git a/src/util/test_payto.c b/src/util/test_payto.c
index 5de0bf355..4dc73a964 100644
--- a/src/util/test_payto.c
+++ b/src/util/test_payto.c
@@ -48,6 +48,8 @@ main (int argc,
                     NULL);
   GNUNET_assert (NULL ==
                  TALER_iban_validate ("FR1420041010050500013M02606"));
+  GNUNET_assert (NULL ==
+                 TALER_iban_validate ("DE89370400440532013000"));
   r = TALER_xtalerbank_account_from_payto (
     "payto://x-taler-bank/localhost:1080/alice");
   CHECK ("alice",