3288. [bug] dlz_destroy() function wasn't correctly registered

by the DLZ dlopen driver. [RT #28056]

bin/tests/system/dlzexternal/tests.sh

@@ -60,4 +60,14 @@ addr=`eval echo $out | cut -f1 -d'#'`
 [ "$ret" -eq 0 ] || echo "I:failed"
 status=`expr $status + $ret`
 
+echo "I:testing DLZ driver is cleaned up on reload"
+$RNDC -c ../common/rndc.conf -s 10.53.0.1 -p 9953 reload 2>&1 | sed 's/^/I:ns1 /'
+for i in 0 1 2 3 4 5 6 7 8 9; do
+    ret=0
+    grep 'dlz_example: shutting down zone example.nil' ns1/named.run > /dev/null 2>&1 || ret=1
+    [ "$ret" -eq 0 ] && break
+done
+[ "$ret" -eq 0 ] || echo "I:failed"
+status=`expr $status + $ret`
+
 exit $status