'remove the nonce from the store
From "Checking the Nonce"::
When the Relying Party checks the signature on an assertion, the
Relying Party SHOULD ensure that an assertion has not yet
been accepted with the same value for "openid.response_nonce"
from the same OP Endpoint URL.'

def test_badNonce(self):

    nonce = mkNonce()
    (stamp, salt) = splitNonce(nonce)
    self.store.useNonce(self.server_url, stamp, salt)
    self.response = Message.fromOpenIDArgs({'response_nonce': nonce, 'ns': OPENID2_NS})
    self.failUnlessRaises(ProtocolError, self.consumer._idResCheckNonce, self.response, self.endpoint)
