'Create an authority and make a request against it.  Then verify that the
result is a referral, including no records in the answers or additional
sections, but with an I{NS} record in the authority section.'

def _referralTest(self, method):

    subdomain = ('example.' + str(soa_record.mname))
    nameserver = dns.Record_NS('1.2.3.4')
    authority = NoFileAuthority(soa=(str(soa_record.mname), soa_record), records={subdomain: [nameserver]})
    d = getattr(authority, method)(subdomain)
    (answer, authority, additional) = self.successResultOf(d)
    self.assertEqual(answer, [])
    self.assertEqual(authority, [dns.RRHeader(subdomain, dns.NS, ttl=soa_record.expire, payload=nameserver, auth=False)])
    self.assertEqual(additional, [])
