add test

Author: devnexen

ext/dba/tests/gh18247.phpt

@@ -0,0 +1,12 @@
+--TEST--
+GH-18247: dba_open() memory leak on invalid path
+--EXTENSIONS--
+dba
+--FILE--
+<?php
+var_dump(dba_popen('/inexistent', 'r'));
+?>
+--EXPECTF--
+
+Warning: dba_popen(/inexistent): Failed to open stream: No such file or directory in %s on line %d
+bool(false)