[OpenID] XRD/YADIS validator?

[Sam Ruby]

Would people on this list see value in a XRD/YADIS validator?

If syndication is any guide, once the "unwashed masses" start adopting 
this, I see plenty of opportunities for errors: non-memorable namespace 
names, MiXeDcAsE Element names, etc.

If there is value, what I would find helpful is suggestions in the form 
of test cases: documents which either are asserted to be valid, or 
documents which contain specified conditions that should produce a 
specific error or a warning.

An example of a warnings could be "unknown Type":  in theory, any URI is 
valid, but unknown Types may indicate a typo.

Checks can also be made for the presence of elements such as 
openid:Delegate when Type is other than http://openid.net/signon/1.0.

Given such tests, I can quickly build this logic on top of the 
foundation that is the Feed Validator: it already has logic for what 
constitutes a valid URI (or IRI, for that matter).

- Sam Ruby