Checks for attribute nodes.
An AttributeTest checks for an attribute node and its name
and can be of one of these forms:
attribute() and attribute(*) match any single
attribute node, regardless of its name or type.
attribute(QName) matches any
attribute node whose name is QName, regardless of its type.
The attribute test attribute(id) matches any attribute
node whose name is "id".
The following construct(s) refer to this construct:
