#data
<source xmlns="http://www.w3.org/2005/Atom">
  <!---->hoge<!---->
</source>
#errors
/source/"hoge";character not allowed;m

#data
<source xmlns="http://www.w3.org/2005/Atom">
  <p xmlns="http://www.w3.org/1999/xhtml">a</p>
</source>
#errors
/source/p;element not allowed;m

#data
<source xmlns="http://www.w3.org/2005/Atom">
  <p xmlns=""/>
</source>
#errors
/source/p;unknown namespace element;u

#data
<source xmlns="http://www.w3.org/2005/Atom">
  <p xmlns="http://foo/"/>
</source>
#errors
/source/p;unknown namespace element;u