# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Test cases for L{twisted.names.server}.
"""

from zope.interface.verify import verifyClass

from twisted.internet import defer
from twisted.internet.interfaces import IProtocolFactory
from twisted.names import dns, error, resolve, server
from twisted.python import failure, log
from twisted.trial import unittest



class RaisedArguments(Exception):
    """
    An exception containing the arguments raised by L{raiser}.
    """
    def __init__(self, args, kwargs):
        self.args = args
        self.kwargs = kwargs



def raiser(*args, **kwargs):
    """
    Raise a L{RaisedArguments} exception containing the supplied arguments.

    Used as a fake when testing the call signatures of  methods and functions.
    """
    raise RaisedArguments(args, kwargs)



class NoResponseDNSServerFactory(server.DNSServerFactory):
    """
    A L{server.DNSServerFactory} subclass which does not attempt to reply to any
    received messages.

    Used for testing logged messages in C{messageReceived} without having to
    fake or patch the preceding code which attempts to deliver a response
    message.
    """
    def allowQuery(self, message, protocol, address):
        """
        Deny all queries.

        @param message: See L{server.DNSServerFactory.allowQuery}
        @param protocol: See L{server.DNSServerFactory.allowQuery}
        @param address: See L{server.DNSServerFactory.allowQuery}

        @return: L{False}
        @rtype: L{bool}
        """
        return False


    def sendReply(self, protocol, message, address):
        """
        A noop send reply.

        @param protocol: See L{server.DNSServerFactory.sendReply}
        @param message: See L{server.DNSServerFactory.sendReply}
        @param address: See L{server.DNSServerFactory.sendReply}
        """



class RaisingDNSServerFactory(server.DNSServerFactory):
    """
    A L{server.DNSServerFactory} subclass whose methods raise an exception
    containing the supplied arguments.

    Used for stopping L{messageReceived} and testing the arguments supplied to
    L{allowQuery}.
    """

    class AllowQueryArguments(Exception):
        """
        Contains positional and keyword arguments in C{args}.
        """

    def allowQuery(self, *args, **kwargs):
        """
        Raise the arguments supplied to L{allowQuery}.

        @param args: Positional arguments which will be recorded in the raised
            exception.
        @type args: L{tuple}

        @param kwargs: Keyword args which will be recorded in the raised
            exception.
        @type kwargs: L{dict}
        """
        raise self.AllowQueryArguments(args, kwargs)



class RaisingProtocol(object):
    """
    A partial fake L{IProtocol} whose methods raise an exception containing the
    supplied arguments.
    """
    class WriteMessageArguments(Exception):
        """
        Contains positional and keyword arguments in C{args}.
        """

    def writeMessage(self, *args, **kwargs):
        """
        Raises the supplied arguments.

        @param args: Positional arguments
        @type args: L{tuple}

        @param kwargs: Keyword args
        @type kwargs: L{dict}
        """
        raise self.WriteMessageArguments(args, kwargs)



class NoopProtocol(object):
    """
    A partial fake L{dns.DNSProtocolMixin} with a noop L{writeMessage} method.
    """
    def writeMessage(self, *args, **kwargs):
        """
        A noop version of L{dns.DNSProtocolMixin.writeMessage}.

        @param args: Positional arguments
        @type args: L{tuple}

        @param kwargs: Keyword args
        @type kwargs: L{dict}
        """



class RaisingResolver(object):
    """
    A partial fake L{IResolver} whose methods raise an exception containing the
    supplied arguments.
    """
    class QueryArguments(Exception):
        """
        Contains positional and keyword arguments in C{args}.
        """


    def query(self, *args, **kwargs):
        """
        Raises the supplied arguments.

        @param args: Positional arguments
        @type args: L{tuple}

        @param kwargs: Keyword args
        @type kwargs: L{dict}
        """
        raise self.QueryArguments(args, kwargs)



class RaisingCache(object):
    """
    A partial fake L{twisted.names.cache.Cache} whose methods raise an exception
    containing the supplied arguments.
    """
    class CacheResultArguments(Exception):
        """
        Contains positional and keyword arguments in C{args}.
        """


    def cacheResult(self, *args, **kwargs):
        """
        Raises the supplied arguments.

        @param args: Positional arguments
        @type args: L{tuple}

        @param kwargs: Keyword args
        @type kwargs: L{dict}
        """
        raise self.CacheResultArguments(args, kwargs)



def assertLogMessage(testCase, expectedMessages, callable, *args, **kwargs):
    """
    Assert that the callable logs the expected messages when called.

    XXX: Put this somewhere where it can be re-used elsewhere. See #6677.

    @param testCase: The test case controlling the test which triggers the
        logged messages and on which assertions will be called.
    @type testCase: L{unittest.SynchronousTestCase}

    @param expectedMessages: A L{list} of the expected log messages
    @type expectedMessages: L{list}

    @param callable: The function which is expected to produce the
        C{expectedMessages} when called.
    @type callable: L{callable}

    @param args: Positional arguments to be passed to C{callable}.
    @type args: L{list}

    @param kwargs: Keyword arguments to be passed to C{callable}.
    @type kwargs: L{dict}
    """
    loggedMessages = []
    log.addObserver(loggedMessages.append)
    testCase.addCleanup(log.removeObserver, loggedMessages.append)

    callable(*args, **kwargs)

    testCase.assertEqual(
        [m['message'][0] for m in loggedMessages],
        expectedMessages)



class DNSServerFactoryTests(unittest.TestCase):
    """
    Tests for L{server.DNSServerFactory}.
    """
    def test_resolverType(self):
        """
        L{server.DNSServerFactory.resolver} is a L{resolve.ResolverChain}
        instance
        """
        self.assertIsInstance(
            server.DNSServerFactory().resolver,
            resolve.ResolverChain)


    def test_resolverDefaultEmpty(self):
        """
        L{server.DNSServerFactory.resolver} is an empty L{resolve.ResolverChain}
        by default.
        """
        self.assertEqual(
            server.DNSServerFactory().resolver.resolvers,
            [])


    def test_authorities(self):
        """
        L{server.DNSServerFactory.__init__} accepts an C{authorities}
        argument. The value of this argument is a list and is used to extend the
        C{resolver} L{resolve.ResolverChain}.
        """
        dummyResolver = object()
        self.assertEqual(
            server.DNSServerFactory(
                authorities=[dummyResolver]).resolver.resolvers,
            [dummyResolver])


    def test_caches(self):
        """
        L{server.DNSServerFactory.__init__} accepts a C{caches} argument. The
        value of this argument is a list and is used to extend the C{resolver}
        L{resolve.ResolverChain}.
        """
        dummyResolver = object()
        self.assertEqual(
            server.DNSServerFactory(
                caches=[dummyResolver]).resolver.resolvers,
            [dummyResolver])


    def test_clients(self):
        """
        L{server.DNSServerFactory.__init__} accepts a C{clients} argument. The
        value of this argument is a list and is used to extend the C{resolver}
        L{resolve.ResolverChain}.
        """
        dummyResolver = object()
        self.assertEqual(
            server.DNSServerFactory(
                clients=[dummyResolver]).resolver.resolvers,
            [dummyResolver])


    def test_resolverOrder(self):
        """
        L{server.DNSServerFactory.resolver} contains an ordered list of
        authorities, caches and clients.
        """
        # Use classes here so that we can see meaningful names in test results
        class DummyAuthority(object):
            pass

        class DummyCache(object):
            pass

        class DummyClient(object):
            pass

        self.assertEqual(
            server.DNSServerFactory(
                authorities=[DummyAuthority],
                caches=[DummyCache],
                clients=[DummyClient]).resolver.resolvers,
            [DummyAuthority, DummyCache, DummyClient])


    def test_cacheDefault(self):
        """
        L{server.DNSServerFactory.cache} is L{None} by default.
        """
        self.assertIs(server.DNSServerFactory().cache, None)


    def test_cacheOverride(self):
        """
        L{server.DNSServerFactory.__init__} assigns the last object in the
        C{caches} list to L{server.DNSServerFactory.cache}.
        """
        dummyResolver = object()
        self.assertEqual(
            server.DNSServerFactory(caches=[object(), dummyResolver]).cache,
            dummyResolver)


    def test_canRecurseDefault(self):
        """
        L{server.DNSServerFactory.canRecurse} is a flag indicating that this
        server is capable of performing recursive DNS lookups. It defaults to
        L{False}.
        """
        self.assertEqual(server.DNSServerFactory().canRecurse, False)


    def test_canRecurseOverride(self):
        """
        L{server.DNSServerFactory.__init__} sets C{canRecurse} to L{True} if it
        is supplied with C{clients}.
        """
        self.assertEqual(
            server.DNSServerFactory(clients=[None]).canRecurse, True)


    def test_verboseDefault(self):
        """
        L{server.DNSServerFactory.verbose} defaults to L{False}.
        """
        self.assertEqual(server.DNSServerFactory().verbose, False)


    def test_verboseOverride(self):
        """
        L{server.DNSServerFactory.__init__} accepts a C{verbose} argument which
        overrides L{server.DNSServerFactory.verbose}.
        """
        self.assertEqual(server.DNSServerFactory(verbose=True).verbose, True)


    def test_interface(self):
        """
        L{server.DNSServerFactory} implements L{IProtocolFactory}.
        """
        self.assertTrue(verifyClass(IProtocolFactory, server.DNSServerFactory))


    def test_defaultProtocol(self):
        """
        L{server.DNSServerFactory.protocol} defaults to L{dns.DNSProtocol}.
        """
        self.assertIs(server.DNSServerFactory.protocol, dns.DNSProtocol)


    def test_buildProtocolProtocolOverride(self):
        """
        L{server.DNSServerFactory.buildProtocol} builds a protocol by calling
        L{server.DNSServerFactory.protocol} with its self as a positional
        argument.
        """
        class FakeProtocol(object):
            factory = None
            args = None
            kwargs = None

        stubProtocol = FakeProtocol()

        def fakeProtocolFactory(*args, **kwargs):
            stubProtocol.args = args
            stubProtocol.kwargs = kwargs
            return stubProtocol

        f = server.DNSServerFactory()
        f.protocol = fakeProtocolFactory
        p = f.buildProtocol(addr=None)

        self.assertEqual(
            (stubProtocol, (f,), {}),
            (p, p.args, p.kwargs)
        )


    def test_verboseLogQuiet(self):
        """
        L{server.DNSServerFactory._verboseLog} does not log messages unless
        C{verbose > 0}.
        """
        f = server.DNSServerFactory()
        assertLogMessage(
            self,
            [],
            f._verboseLog,
            'Foo Bar'
        )


    def test_verboseLogVerbose(self):
        """
        L{server.DNSServerFactory._verboseLog} logs a message if C{verbose > 0}.
        """
        f = server.DNSServerFactory(verbose=1)
        assertLogMessage(
            self,
            ['Foo Bar'],
            f._verboseLog,
            'Foo Bar'
        )


    def test_messageReceivedLoggingNoQuery(self):
        """
        L{server.DNSServerFactory.messageReceived} logs about an empty query if
        the message had no queries and C{verbose} is C{>0}.
        """
        m = dns.Message()
        f = NoResponseDNSServerFactory(verbose=1)

        assertLogMessage(
            self,
            ["Empty query from ('192.0.2.100', 53)"],
            f.messageReceived,
            message=m, proto=None, address=('192.0.2.100', 53))


    def test_messageReceivedLogging1(self):
        """
        L{server.DNSServerFactory.messageReceived} logs the query types of all
        queries in the message if C{verbose} is set to C{1}.
        """
        m = dns.Message()
        m.addQuery(name='example.com', type=dns.MX)
        m.addQuery(name='example.com', type=dns.AAAA)
        f = NoResponseDNSServerFactory(verbose=1)

        assertLogMessage(
            self,
            ["MX AAAA query from ('192.0.2.100', 53)"],
            f.messageReceived,
            message=m, proto=None, address=('192.0.2.100', 53))


    def test_messageReceivedLogging2(self):
        """
        L{server.DNSServerFactory.messageReceived} logs the repr of all queries
        in the message if C{verbose} is set to C{2}.
        """
        m = dns.Message()
        m.addQuery(name='example.com', type=dns.MX)
        m.addQuery(name='example.com', type=dns.AAAA)
        f = NoResponseDNSServerFactory(verbose=2)

        assertLogMessage(
            self,
            ["<Query example.com MX IN> "
             "<Query example.com AAAA IN> query from ('192.0.2.100', 53)"],
            f.messageReceived,
            message=m, proto=None, address=('192.0.2.100', 53))


    def test_messageReceivedTimestamp(self):
        """
        L{server.DNSServerFactory.messageReceived} assigns a unix timestamp to
        the received message.
        """
        m = dns.Message()
        f = NoResponseDNSServerFactory()
        t = object()
        self.patch(server.time, 'time', lambda: t)
        f.messageReceived(message=m, proto=None, address=None)

        self.assertEqual(m.timeReceived, t)


    def test_messageReceivedAllowQuery(self):
        """
        L{server.DNSServerFactory.messageReceived} passes all messages to
        L{server.DNSServerFactory.allowQuery} along with the receiving protocol
        and origin address.
        """
        message = dns.Message()
        dummyProtocol = object()
        dummyAddress = object()

        f = RaisingDNSServerFactory()
        e = self.assertRaises(
            RaisingDNSServerFactory.AllowQueryArguments,
            f.messageReceived,
            message=message, proto=dummyProtocol, address=dummyAddress)
        args, kwargs = e.args
        self.assertEqual(args, (message, dummyProtocol, dummyAddress))
        self.assertEqual(kwargs, {})


    def test_allowQueryFalse(self):
        """
        If C{allowQuery} returns C{False},
        L{server.DNSServerFactory.messageReceived} calls L{server.sendReply}
        with a message whose C{rCode} is L{dns.EREFUSED}.
        """
        class SendReplyException(Exception):
            pass

        class RaisingDNSServerFactory(server.DNSServerFactory):
            def allowQuery(self, *args, **kwargs):
                return False

            def sendReply(self, *args, **kwargs):
                raise SendReplyException(args, kwargs)

        f = RaisingDNSServerFactory()
        e = self.assertRaises(
            SendReplyException,
            f.messageReceived,
            message=dns.Message(), proto=None, address=None)
        (proto, message, address), kwargs = e.args

        self.assertEqual(message.rCode, dns.EREFUSED)


    def _messageReceivedTest(self, methodName, message):
        """
        Assert that the named method is called with the given message when it is
        passed to L{DNSServerFactory.messageReceived}.

        @param methodName: The name of the method which is expected to be
            called.
        @type methodName: L{str}

        @param message: The message which is expected to be passed to the
            C{methodName} method.
        @type message: L{dns.Message}
        """
        # Make it appear to have some queries so that
        # DNSServerFactory.allowQuery allows it.
        message.queries = [None]

        receivedMessages = []
        def fakeHandler(message, protocol, address):
            receivedMessages.append((message, protocol, address))

        protocol = NoopProtocol()
        factory = server.DNSServerFactory(None)
        setattr(factory, methodName, fakeHandler)
        factory.messageReceived(message, protocol)
        self.assertEqual(receivedMessages, [(message, protocol, None)])


    def test_queryMessageReceived(self):
        """
        L{DNSServerFactory.messageReceived} passes messages with an opcode of
        C{OP_QUERY} on to L{DNSServerFactory.handleQuery}.
        """
        self._messageReceivedTest(
            'handleQuery', dns.Message(opCode=dns.OP_QUERY))


    def test_inverseQueryMessageReceived(self):
        """
        L{DNSServerFactory.messageReceived} passes messages with an opcode of
        C{OP_INVERSE} on to L{DNSServerFactory.handleInverseQuery}.
        """
        self._messageReceivedTest(
            'handleInverseQuery', dns.Message(opCode=dns.OP_INVERSE))


    def test_statusMessageReceived(self):
        """
        L{DNSServerFactory.messageReceived} passes messages with an opcode of
        C{OP_STATUS} on to L{DNSServerFactory.handleStatus}.
        """
        self._messageReceivedTest(
            'handleStatus', dns.Message(opCode=dns.OP_STATUS))


    def test_notifyMessageReceived(self):
        """
        L{DNSServerFactory.messageReceived} passes messages with an opcode of
        C{OP_NOTIFY} on to L{DNSServerFactory.handleNotify}.
        """
        self._messageReceivedTest(
            'handleNotify', dns.Message(opCode=dns.OP_NOTIFY))


    def test_updateMessageReceived(self):
        """
        L{DNSServerFactory.messageReceived} passes messages with an opcode of
        C{OP_UPDATE} on to L{DNSServerFactory.handleOther}.

        This may change if the implementation ever covers update messages.
        """
        self._messageReceivedTest(
            'handleOther', dns.Message(opCode=dns.OP_UPDATE))


    def test_connectionTracking(self):
        """
        The C{connectionMade} and C{connectionLost} methods of
        L{DNSServerFactory} cooperate to keep track of all L{DNSProtocol}
        objects created by a factory which are connected.
        """
        protoA, protoB = object(), object()
        factory = server.DNSServerFactory()
        factory.connectionMade(protoA)
        self.assertEqual(factory.connections, [protoA])
        factory.connectionMade(protoB)
        self.assertEqual(factory.connections, [protoA, protoB])
        factory.connectionLost(protoA)
        self.assertEqual(factory.connections, [protoB])
        factory.connectionLost(protoB)
        self.assertEqual(factory.connections, [])


    def test_handleQuery(self):
        """
        L{server.DNSServerFactory.handleQuery} takes the first query from the
        supplied message and dispatches it to
        L{server.DNSServerFactory.resolver.query}.
        """
        m = dns.Message()
        m.addQuery(b'one.example.com')
        m.addQuery(b'two.example.com')
        f = server.DNSServerFactory()
        f.resolver = RaisingResolver()

        e = self.assertRaises(
            RaisingResolver.QueryArguments,
            f.handleQuery,
            message=m, protocol=NoopProtocol(), address=None)
        (query,), kwargs = e.args
        self.assertEqual(query, m.queries[0])


    def test_handleQueryCallback(self):
        """
        L{server.DNSServerFactory.handleQuery} adds
        L{server.DNSServerFactory.resolver.gotResolverResponse} as a callback to
        the deferred returned by L{server.DNSServerFactory.resolver.query}. It
        is called with the query response, the original protocol, message and
        origin address.
        """
        f = server.DNSServerFactory()

        d = defer.Deferred()
        class FakeResolver(object):
            def query(self, *args, **kwargs):
                return d
        f.resolver = FakeResolver()

        gotResolverResponseArgs = []
        def fakeGotResolverResponse(*args, **kwargs):
            gotResolverResponseArgs.append((args, kwargs))
        f.gotResolverResponse = fakeGotResolverResponse

        m = dns.Message()
        m.addQuery(b'one.example.com')
        stubProtocol = NoopProtocol()
        dummyAddress = object()

        f.handleQuery(message=m, protocol=stubProtocol, address=dummyAddress)

        dummyResponse = object()
        d.callback(dummyResponse)

        self.assertEqual(
            gotResolverResponseArgs,
            [((dummyResponse, stubProtocol, m, dummyAddress), {})])


    def test_handleQueryErrback(self):
        """
        L{server.DNSServerFactory.handleQuery} adds
        L{server.DNSServerFactory.resolver.gotResolverError} as an errback to
        the deferred returned by L{server.DNSServerFactory.resolver.query}. It
        is called with the query failure, the original protocol, message and
        origin address.
        """
        f = server.DNSServerFactory()

        d = defer.Deferred()
        class FakeResolver(object):
            def query(self, *args, **kwargs):
                return d
        f.resolver = FakeResolver()

        gotResolverErrorArgs = []
        def fakeGotResolverError(*args, **kwargs):
            gotResolverErrorArgs.append((args, kwargs))
        f.gotResolverError = fakeGotResolverError

        m = dns.Message()
        m.addQuery(b'one.example.com')
        stubProtocol = NoopProtocol()
        dummyAddress = object()

        f.handleQuery(message=m, protocol=stubProtocol, address=dummyAddress)

        stubFailure = failure.Failure(Exception())
        d.errback(stubFailure)

        self.assertEqual(
            gotResolverErrorArgs,
            [((stubFailure, stubProtocol, m, dummyAddress), {})])


    def test_gotResolverResponse(self):
        """
        L{server.DNSServerFactory.gotResolverResponse} accepts a tuple of
        resource record lists and triggers a response message containing those
        resource record lists.
        """
        f = server.DNSServerFactory()
        answers = []
        authority = []
        additional = []
        e = self.assertRaises(
            RaisingProtocol.WriteMessageArguments,
            f.gotResolverResponse,
            (answers, authority, additional),
            protocol=RaisingProtocol(), message=dns.Message(), address=None)
        (message,), kwargs = e.args

        self.assertIs(message.answers, answers)
        self.assertIs(message.authority, authority)
        self.assertIs(message.additional, additional)


    def test_gotResolverResponseCallsResponseFromMessage(self):
        """
        L{server.DNSServerFactory.gotResolverResponse} calls
        L{server.DNSServerFactory._responseFromMessage} to generate a response.
        """
        factory = NoResponseDNSServerFactory()
        factory._responseFromMessage = raiser

        request = dns.Message()
        request.timeReceived = 1

        e = self.assertRaises(
            RaisedArguments,
            factory.gotResolverResponse,
            ([], [], []),
            protocol=None, message=request, address=None
        )
        self.assertEqual(
            ((), dict(message=request, rCode=dns.OK,
                      answers=[], authority=[], additional=[])),
            (e.args, e.kwargs)
        )


    def test_responseFromMessageNewMessage(self):
        """
        L{server.DNSServerFactory._responseFromMessage} generates a response
        message which is a copy of the request message.
        """
        factory = server.DNSServerFactory()
        request = dns.Message(answer=False, recAv=False)
        response = factory._responseFromMessage(message=request),

        self.assertIsNot(request, response)


    def test_responseFromMessageRecursionAvailable(self):
        """
        L{server.DNSServerFactory._responseFromMessage} generates a response
        message whose C{recAV} attribute is L{True} if
        L{server.DNSServerFactory.canRecurse} is L{True}.
        """
        factory = server.DNSServerFactory()
        factory.canRecurse = True
        response1 = factory._responseFromMessage(
            message=dns.Message(recAv=False))
        factory.canRecurse = False
        response2 = factory._responseFromMessage(
            message=dns.Message(recAv=True))
        self.assertEqual(
            (True, False),
            (response1.recAv, response2.recAv))


    def test_responseFromMessageTimeReceived(self):
        """
        L{server.DNSServerFactory._responseFromMessage} generates a response
        message whose C{timeReceived} attribute has the same value as that found
        on the request.
        """
        factory = server.DNSServerFactory()
        request = dns.Message()
        request.timeReceived = 1234
        response = factory._responseFromMessage(message=request)

        self.assertEqual(request.timeReceived, response.timeReceived)


    def test_responseFromMessageMaxSize(self):
        """
        L{server.DNSServerFactory._responseFromMessage} generates a response
        message whose C{maxSize} attribute has the same value as that found
        on the request.
        """
        factory = server.DNSServerFactory()
        request = dns.Message()
        request.maxSize = 0
        response = factory._responseFromMessage(message=request)

        self.assertEqual(request.maxSize, response.maxSize)


    def test_messageFactory(self):
        """
        L{server.DNSServerFactory} has a C{_messageFactory} attribute which is
        L{dns.Message} by default.
        """
        self.assertIs(dns.Message, server.DNSServerFactory._messageFactory)


    def test_responseFromMessageCallsMessageFactory(self):
        """
        L{server.DNSServerFactory._responseFromMessage} calls
        C{dns._responseFromMessage} to generate a response
        message from the request message. It supplies the request message and
        other keyword arguments which should be passed to the response message
        initialiser.
        """
        factory = server.DNSServerFactory()
        self.patch(dns, '_responseFromMessage', raiser)

        request = dns.Message()
        e = self.assertRaises(
            RaisedArguments,
            factory._responseFromMessage,
            message=request, rCode=dns.OK
        )
        self.assertEqual(
            ((), dict(responseConstructor=factory._messageFactory,
                      message=request, rCode=dns.OK, recAv=factory.canRecurse,
                      auth=False)),
            (e.args, e.kwargs)
        )


    def test_responseFromMessageAuthoritativeMessage(self):
        """
        L{server.DNSServerFactory._responseFromMessage} marks the response
        message as authoritative if any of the answer records are authoritative.
        """
        factory = server.DNSServerFactory()
        response1 = factory._responseFromMessage(
            message=dns.Message(), answers=[dns.RRHeader(auth=True)])
        response2 = factory._responseFromMessage(
            message=dns.Message(), answers=[dns.RRHeader(auth=False)])
        self.assertEqual(
            (True, False),
            (response1.auth, response2.auth),
        )


    def test_gotResolverResponseLogging(self):
        """
        L{server.DNSServerFactory.gotResolverResponse} logs the total number of
        records in the response if C{verbose > 0}.
        """
        f = NoResponseDNSServerFactory(verbose=1)
        answers = [dns.RRHeader()]
        authority = [dns.RRHeader()]
        additional = [dns.RRHeader()]

        assertLogMessage(
            self,
            ["Lookup found 3 records"],
            f.gotResolverResponse,
            (answers, authority, additional),
            protocol=NoopProtocol(), message=dns.Message(), address=None)


    def test_gotResolverResponseCaching(self):
        """
        L{server.DNSServerFactory.gotResolverResponse} caches the response if at
        least one cache was provided in the constructor.
        """
        f = NoResponseDNSServerFactory(caches=[RaisingCache()])

        m = dns.Message()
        m.addQuery(b'example.com')
        expectedAnswers = [dns.RRHeader()]
        expectedAuthority = []
        expectedAdditional = []

        e = self.assertRaises(
            RaisingCache.CacheResultArguments,
            f.gotResolverResponse,
            (expectedAnswers, expectedAuthority, expectedAdditional),
            protocol=NoopProtocol(), message=m, address=None)
        (query, (answers, authority, additional)), kwargs = e.args

        self.assertEqual(query.name.name, b'example.com')
        self.assertIs(answers, expectedAnswers)
        self.assertIs(authority, expectedAuthority)
        self.assertIs(additional, expectedAdditional)


    def test_gotResolverErrorCallsResponseFromMessage(self):
        """
        L{server.DNSServerFactory.gotResolverError} calls
        L{server.DNSServerFactory._responseFromMessage} to generate a response.
        """
        factory = NoResponseDNSServerFactory()
        factory._responseFromMessage = raiser

        request = dns.Message()
        request.timeReceived = 1

        e = self.assertRaises(
            RaisedArguments,
            factory.gotResolverError,
            failure.Failure(error.DomainError()),
            protocol=None, message=request, address=None
        )
        self.assertEqual(
            ((), dict(message=request, rCode=dns.ENAME)),
            (e.args, e.kwargs)
        )


    def _assertMessageRcodeForError(self, responseError, expectedMessageCode):
        """
        L{server.DNSServerFactory.gotResolver} accepts a L{failure.Failure} and
        triggers a response message whose rCode corresponds to the DNS error
        contained in the C{Failure}.

        @param responseError: The L{Exception} instance which is expected to
            trigger C{expectedMessageCode} when it is supplied to
            C{gotResolverError}
        @type responseError: L{Exception}

        @param expectedMessageCode: The C{rCode} which is expected in the
            message returned by C{gotResolverError} in response to
            C{responseError}.
        @type expectedMessageCode: L{int}
        """
        f = server.DNSServerFactory()
        e = self.assertRaises(
            RaisingProtocol.WriteMessageArguments,
            f.gotResolverError,
            failure.Failure(responseError),
            protocol=RaisingProtocol(), message=dns.Message(), address=None)
        (message,), kwargs = e.args

        self.assertEqual(message.rCode, expectedMessageCode)


    def test_gotResolverErrorDomainError(self):
        """
        L{server.DNSServerFactory.gotResolver} triggers a response message with
        an C{rCode} of L{dns.ENAME} if supplied with a L{error.DomainError}.
        """
        self._assertMessageRcodeForError(error.DomainError(), dns.ENAME)


    def test_gotResolverErrorAuthoritativeDomainError(self):
        """
        L{server.DNSServerFactory.gotResolver} triggers a response message with
        an C{rCode} of L{dns.ENAME} if supplied with a
        L{error.AuthoritativeDomainError}.
        """
        self._assertMessageRcodeForError(
            error.AuthoritativeDomainError(), dns.ENAME)


    def test_gotResolverErrorOtherError(self):
        """
        L{server.DNSServerFactory.gotResolver} triggers a response message with
        an C{rCode} of L{dns.ESERVER} if supplied with another type of error and
        logs the error.
        """
        self._assertMessageRcodeForError(KeyError(), dns.ESERVER)
        e = self.flushLoggedErrors(KeyError)
        self.assertEqual(len(e), 1)


    def test_gotResolverErrorLogging(self):
        """
        L{server.DNSServerFactory.gotResolver} logs a message if C{verbose > 0}.
        """
        f = NoResponseDNSServerFactory(verbose=1)
        assertLogMessage(
            self,
            ["Lookup failed"],
            f.gotResolverError,
            failure.Failure(error.DomainError()),
            protocol=NoopProtocol(), message=dns.Message(), address=None)


    def test_gotResolverErrorResetsResponseAttributes(self):
        """
        L{server.DNSServerFactory.gotResolverError} does not allow request
        attributes to leak into the response ie it sends a response with AD, CD
        set to 0 and empty response record sections.
        """
        factory = server.DNSServerFactory()
        responses = []
        factory.sendReply = (
            lambda protocol, response, address: responses.append(response)
        )
        request = dns.Message(authenticData=True, checkingDisabled=True)
        request.answers = [object(), object()]
        request.authority = [object(), object()]
        request.additional = [object(), object()]
        factory.gotResolverError(
            failure.Failure(error.DomainError()),
            protocol=None, message=request, address=None
        )

        self.assertEqual([dns.Message(rCode=3, answer=True)], responses)


    def test_gotResolverResponseResetsResponseAttributes(self):
        """
        L{server.DNSServerFactory.gotResolverResponse} does not allow request
        attributes to leak into the response ie it sends a response with AD, CD
        set to 0 and none of the records in the request answer sections are
        copied to the response.
        """
        factory = server.DNSServerFactory()
        responses = []
        factory.sendReply = (
            lambda protocol, response, address: responses.append(response)
        )
        request = dns.Message(authenticData=True, checkingDisabled=True)
        request.answers = [object(), object()]
        request.authority = [object(), object()]
        request.additional = [object(), object()]

        factory.gotResolverResponse(
            ([], [], []),
            protocol=None, message=request, address=None
        )

        self.assertEqual([dns.Message(rCode=0, answer=True)], responses)


    def test_sendReplyWithAddress(self):
        """
        If L{server.DNSServerFactory.sendReply} is supplied with a protocol
        *and* an address tuple it will supply that address to
        C{protocol.writeMessage}.
        """
        m = dns.Message()
        dummyAddress = object()
        f = server.DNSServerFactory()
        e = self.assertRaises(
            RaisingProtocol.WriteMessageArguments,
            f.sendReply,
            protocol=RaisingProtocol(),
            message=m,
            address=dummyAddress)
        args, kwargs = e.args
        self.assertEqual(args, (m, dummyAddress))
        self.assertEqual(kwargs, {})


    def test_sendReplyWithoutAddress(self):
        """
        If L{server.DNSServerFactory.sendReply} is supplied with a protocol but
        no address tuple it will supply only a message to
        C{protocol.writeMessage}.
        """
        m = dns.Message()
        f = server.DNSServerFactory()
        e = self.assertRaises(
            RaisingProtocol.WriteMessageArguments,
            f.sendReply,
            protocol=RaisingProtocol(),
            message=m,
            address=None)
        args, kwargs = e.args
        self.assertEqual(args, (m,))
        self.assertEqual(kwargs, {})


    def test_sendReplyLoggingNoAnswers(self):
        """
        If L{server.DNSServerFactory.sendReply} logs a "no answers" message if
        the supplied message has no answers.
        """
        self.patch(server.time, 'time', lambda: 2)
        m = dns.Message()
        m.timeReceived = 1
        f = server.DNSServerFactory(verbose=2)
        assertLogMessage(
            self,
            ["Replying with no answers", "Processed query in 1.000 seconds"],
            f.sendReply,
            protocol=NoopProtocol(),
            message=m,
            address=None)


    def test_sendReplyLoggingWithAnswers(self):
        """
        If L{server.DNSServerFactory.sendReply} logs a message for answers,
        authority, additional if the supplied a message has records in any of
        those sections.
        """
        self.patch(server.time, 'time', lambda: 2)
        m = dns.Message()
        m.answers.append(dns.RRHeader(payload=dns.Record_A('127.0.0.1')))
        m.authority.append(dns.RRHeader(payload=dns.Record_A('127.0.0.1')))
        m.additional.append(dns.RRHeader(payload=dns.Record_A('127.0.0.1')))
        m.timeReceived = 1
        f = server.DNSServerFactory(verbose=2)
        assertLogMessage(
            self,
            ['Answers are <A address=127.0.0.1 ttl=None>',
             'Authority is <A address=127.0.0.1 ttl=None>',
             'Additional is <A address=127.0.0.1 ttl=None>',
             'Processed query in 1.000 seconds'],
            f.sendReply,
            protocol=NoopProtocol(),
            message=m,
            address=None)


    def test_handleInverseQuery(self):
        """
        L{server.DNSServerFactory.handleInverseQuery} triggers the sending of a
        response message with C{rCode} set to L{dns.ENOTIMP}.
        """
        f = server.DNSServerFactory()
        e = self.assertRaises(
            RaisingProtocol.WriteMessageArguments,
            f.handleInverseQuery,
            message=dns.Message(), protocol=RaisingProtocol(), address=None)
        (message,), kwargs = e.args

        self.assertEqual(message.rCode, dns.ENOTIMP)


    def test_handleInverseQueryLogging(self):
        """
        L{server.DNSServerFactory.handleInverseQuery} logs the message origin
        address if C{verbose > 0}.
        """
        f = NoResponseDNSServerFactory(verbose=1)
        assertLogMessage(
            self,
            ["Inverse query from ('::1', 53)"],
            f.handleInverseQuery,
            message=dns.Message(),
            protocol=NoopProtocol(),
            address=('::1', 53))


    def test_handleStatus(self):
        """
        L{server.DNSServerFactory.handleStatus} triggers the sending of a
        response message with C{rCode} set to L{dns.ENOTIMP}.
        """
        f = server.DNSServerFactory()
        e = self.assertRaises(
            RaisingProtocol.WriteMessageArguments,
            f.handleStatus,
            message=dns.Message(), protocol=RaisingProtocol(), address=None)
        (message,), kwargs = e.args

        self.assertEqual(message.rCode, dns.ENOTIMP)


    def test_handleStatusLogging(self):
        """
        L{server.DNSServerFactory.handleStatus} logs the message origin address
        if C{verbose > 0}.
        """
        f = NoResponseDNSServerFactory(verbose=1)
        assertLogMessage(
            self,
            ["Status request from ('::1', 53)"],
            f.handleStatus,
            message=dns.Message(),
            protocol=NoopProtocol(),
            address=('::1', 53))


    def test_handleNotify(self):
        """
        L{server.DNSServerFactory.handleNotify} triggers the sending of a
        response message with C{rCode} set to L{dns.ENOTIMP}.
        """
        f = server.DNSServerFactory()
        e = self.assertRaises(
            RaisingProtocol.WriteMessageArguments,
            f.handleNotify,
            message=dns.Message(), protocol=RaisingProtocol(), address=None)
        (message,), kwargs = e.args

        self.assertEqual(message.rCode, dns.ENOTIMP)


    def test_handleNotifyLogging(self):
        """
        L{server.DNSServerFactory.handleNotify} logs the message origin address
        if C{verbose > 0}.
        """
        f = NoResponseDNSServerFactory(verbose=1)
        assertLogMessage(
            self,
            ["Notify message from ('::1', 53)"],
            f.handleNotify,
            message=dns.Message(),
            protocol=NoopProtocol(),
            address=('::1', 53))


    def test_handleOther(self):
        """
        L{server.DNSServerFactory.handleOther} triggers the sending of a
        response message with C{rCode} set to L{dns.ENOTIMP}.
        """
        f = server.DNSServerFactory()
        e = self.assertRaises(
            RaisingProtocol.WriteMessageArguments,
            f.handleOther,
            message=dns.Message(), protocol=RaisingProtocol(), address=None)
        (message,), kwargs = e.args

        self.assertEqual(message.rCode, dns.ENOTIMP)


    def test_handleOtherLogging(self):
        """
        L{server.DNSServerFactory.handleOther} logs the message origin address
        if C{verbose > 0}.
        """
        f = NoResponseDNSServerFactory(verbose=1)
        assertLogMessage(
            self,
            ["Unknown op code (0) from ('::1', 53)"],
            f.handleOther,
            message=dns.Message(),
            protocol=NoopProtocol(),
            address=('::1', 53))
