Test case Nothing-002 incorrectly labeled by WebOnt

After prompting by Claudio Corona I investigated the test case
[WebOnt-Nothing-002], pulled forward from the WebOnt test suite.  The
WebOnt group labeled the conclusion ontology as OWL DL, which I
believe is incorrect.  The reverse mapping specified by our RDF
Mapping doc produces the following

Ontology(
  EquivalentClasses( owl:Nothing owl:Nothing )
)

Since the structural specification says that an equivalent class axiom
has two or more class expressions in an unordered set, the axiom above
is not valid, therefore the RDF graph cannot be an OWL DL ontology
document.

I will be updating the test metadata to indicate that the conclusion
ontology is not valid OWL 2 DL.  If anyone feels this is incorrect,
please reply.
-- 
Mike Smith

Clark & Parsia

[WebOnt-Nothing-002]
http://km.aifb.uni-karlsruhe.de/projects/owltests/index.php/TestCase:WebOnt-Nothing-002