diff --git a/tests/scripts/test016-subref b/tests/scripts/test016-subref
index 79d2eb6bab..29d6a1ee03 100755
--- a/tests/scripts/test016-subref
+++ b/tests/scripts/test016-subref
@@ -14,6 +14,7 @@
 ## <http://www.OpenLDAP.org/license.html>.
 
 RCODE=10
+test $BACKEND = null && RCODE=0
 
 echo "running defines.sh"
 . $SRCDIR/scripts/defines.sh