#data
<picture xmlns="http://www.w3.org/1999/xhtml">
  <source srcset="foo" media="screen"/>
  <img src="a" alt="b"/>
</picture>
#errors
/picture/source/@srcset;unknown attribute;u

#data
<picture xmlns="http://www.w3.org/1999/xhtml">
  <source srcset="foo" media="screen and (hoge)"/>
  <img src="a" alt="b"/>
</picture>
#errors
/picture/source/@srcset;unknown attribute;u
/picture/source/@media;mq:feature:unknown;m

#data
<picture xmlns="http://www.w3.org/1999/xhtml">
  <source srcset="foo" sizes=""/>
  <img src="a" alt="b"/>
</picture>
#errors
/picture/source/@srcset;unknown attribute;u
/picture/source/@sizes;unknown attribute;u

#data
<picture xmlns="http://www.w3.org/1999/xhtml">
  <source srcset="foo" type="image/png"/>
  <img src="a" alt="b"/>
</picture>
#errors
/picture/source/@srcset;unknown attribute;u

#data
<picture xmlns="http://www.w3.org/1999/xhtml">
  <source srcset="foo" type="image/png?"/>
  <img src="a" alt="b"/>
</picture>
#errors
/picture/source/@srcset;unknown attribute;u
/picture/source/@type;MIME type:bad char after subtype;m

#data
<picture xmlns="http://www.w3.org/1999/xhtml">
  <source srcset="foo" src="image/png?"/>
  <img src="a" alt="b"/>
</picture>
#errors
/picture/source/@srcset;unknown attribute;u
/picture/source/@src;attribute not allowed:media source;m

#data
<picture xmlns="http://www.w3.org/1999/xhtml">
  <source src="image/png?"/>
  <img src="a" alt="b"/>
</picture>
#errors
/picture/source;attribute missing;srcset;m
/picture/source/@src;attribute not allowed:media source;m