'L{Resolver.lookupNameservers} is like L{Resolver.lookupAddress}, except
it queries for I{NS} records instead of I{A} records.'

def test_lookupNameservers(self):

    servers = {('1.1.2.3', 53): {('example.com', A): {'rCode': ENAME}, ('example.com', NS): {'answers': [('example.com', Record_NS('ns1.example.com'))]}}}
    resolver = self._getResolver(servers)
    d = resolver.lookupNameservers('example.com')
    def getOneName(results):
        (ans, auth, add) = results
        return ans[0].payload.name
    d.addCallback(getOneName)
    d.addCallback(self.assertEqual, Name('ns1.example.com'))
    return d
