I found a bug in XmlTextReader where it doesn't throw an XmlException for the following xml:

<?xml version="1.0" ?><doc>]]></doc>

(both the xml 1.0 and xml 1.1 spec prohibit the sequence ']]>' from appearing in element content).

I added a new class to avoid cluttering the existing TestXmlTextReader class with stuff (since the number of checks to do on parsing is very large). Here included are the 2 context diffs, one for the file and one to add it to the test suite in TestXml.cs.