'Similar to L{test_serializedAttributeWithTag}, but for the additional
complexity where the tag which is the attribute value itself has an
attribute value which contains bytes which require substitution.'

def test_serializedAttributeWithTagWithAttribute(self):

    flattened = self.assertFlattensImmediately(tags.img(src=tags.a(href='<>&"')), '<img    src="&lt;a    href=&quot;&amp;lt;&amp;gt;&amp;amp;&amp;quot;&quot;&gt;&lt;/a&gt;"    />')
    self.assertXMLEqual(XML(flattened).attrib['src'], '<a    href="&lt;&gt;&amp;&quot;"></a>')
