Trying to run this test against this code. I get an error about the reactor being unclean. What does that mean in this context?

proxyjson_server.py

from twisted.internet.endpoints import TCP4ServerEndpoint
from twisted.internet.error import CannotListenError
from twisted.internet.protocol import Protocol, Factory
from twisted.internet import reactor
import simplejson as json

# Ports available for proxy purposes.
low_port = 5000
high_port = 5100


class EchoFactory(Factory):
    def __init__(self, proxy):
        self.proxy = proxy

    def buildProtocol(self, addr):
        return Echo(self)


class Echo(Protocol):
    def __init__(self, factory):
        self.factory = factory

    def connectionMade(self):
        self.transport.write(self.factory.proxy.output)
        self.transport.loseConnection()

    def connectionLost(self, reason):
        self.factory.proxy.open_port.stopListening()
        self.factory.proxy.ports.append(self.factory.proxy.dport)


class ProxyFactory(Factory):
    def buildProtocol(self, addr):
        return Proxy(self)


class Proxy(Protocol):
    ports = [x for x in xrange(low_port, high_port)]
    in_use = []

    def __init__(self, factory):
        self.dport = None
        self.factory = factory

    def connectionMade(self):
        while not self.dport:
            try:
                self.dport = Proxy.ports.pop()
            except IndexError:
                self.transport.write("No ports available!")
                self.transport.abortConnection()
            try:
                self.endpoint = TCP4ServerEndpoint(reactor, self.dport,
                                                   backlog=1)
            except CannotListenError:
                self.dport = None

    def dataReceived(self, data):
        self.output = data
        # abort connection if json is invalid?
        self.transport.write(str(self.dport))
        self.endpoint.listen(EchoFactory(self)).addCallback(self.set_open_port)
        self.transport.loseConnection()

    def set_open_port(self, result):
        self.open_port = result

test_proxyjson.py

from proxyjson_server import ProxyFactory, EchoFactory
from twisted.trial import unittest
from twisted.test import proto_helpers
from mock import patch, MagicMock


class ProxyJsonFactoryTestCase(unittest.TestCase):
    def setUp(self):
        factory = ProxyFactory()
        self.proto = factory.buildProtocol(('127.0.0.1', 0))
        self.tr = proto_helpers.StringTransport()
        self.proto.makeConnection(self.tr)

    # The following test mocks up a connection to the port returned by
    # the proxy.  The object that listens for the connection has the
    # correct return value in it, so we just check for that value.

    @patch('proxyjson_server.Echo')
    def test_proxyjson(self, proxy_echo):
        instring = 'hi'
        self.proto.dataReceived(instring)
        inport = int(self.tr.value())
        echof = EchoFactory(self.proto)
        self.echop = echof.buildProtocol(('127.0.0.1', inport))
        args, kwargs = proxy_echo.call_args
        self.assertEqual(args[0].proxy.output, instring)

transcript

(twistedauthproxy)jmt@cyan:~/crazy/twistedauthproxy$ trial test.test_proxyjson
test.test_proxyjson
  ProxyJsonFactoryTestCase
    test_proxyjson ...                                                     [OK]
                                                 [ERROR]

===============================================================================
[ERROR]
Traceback (most recent call last):
Failure: twisted.trial.util.DirtyReactorAggregateError: Reactor was unclean.
Selectables:
<<class 'twisted.internet.tcp.Port'> of proxyjson_server.EchoFactory on 5099>

test.test_proxyjson.ProxyJsonFactoryTestCase.test_proxyjson
-------------------------------------------------------------------------------
Ran 1 tests in 0.007s

FAILED (errors=1, successes=1)
(twistedauthproxy)jmt@cyan:~/crazy/twistedauthproxy$