add forgotten test

Author: ndossche

ext/dom/tests/modern/common/attr_named_node_map_cache.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Attribute named node map cache
+--EXTENSIONS--
+dom
+--FILE--
+<?php
+
+$dom = Dom\XMLDocument::createFromString('<root a="1" b="2" c="3"/>');
+$attrs = $dom->documentElement->attributes;
+var_dump($attrs[1]->nodeName);
+$dom->documentElement->removeAttribute('b');
+var_dump($attrs[1]->nodeName);
+
+?>
+--EXPECT--
+string(1) "b"
+string(1) "c"