before: <a/>
after: <a><b>abc</b></a>
before: <a><b/></a>
after: <a><b>abc</b></a>
before: <a><b>foobar</b></a>
after: <a><b>abc</b></a>
before: <a><b><x1>x1</x1><x2>x2</x2></b></a>
after: <a><b>abc</b></a>
before: <a><b x="1"/></a>
after: <a><b x="1">abc</b></a>
before: <a>xxx<foo>yyy</foo>zzz</a>
after: <a>xxx<foo>yyy</foo>zzz<b>abc</b></a>
before: <a/>
xml.name: abc
after: <a><name>abc</name></a>
before: <a><b/></a>
after: <a><b><hello>world</hello></b></a>
