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# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.
"""
Tests for L{twisted.test.iosim}.
"""
from zope.interface import implementer
from twisted.internet.interfaces import IPushProducer
from twisted.internet.protocol import Protocol
from twisted.test.iosim import FakeTransport, connect
from twisted.trial.unittest import TestCase
class FakeTransportTests(TestCase):
"""
Tests for L{FakeTransport}.
"""
def test_connectionSerial(self):
"""
Each L{FakeTransport} receives a serial number that uniquely identifies
it.
"""
a = FakeTransport(object(), True)
b = FakeTransport(object(), False)
self.assertIsInstance(a.serial, int)
self.assertIsInstance(b.serial, int)
self.assertNotEqual(a.serial, b.serial)
def test_writeSequence(self):
"""
L{FakeTransport.writeSequence} will write a sequence of L{bytes} to the
transport.
"""
a = FakeTransport(object(), False)
a.write(b"a")
a.writeSequence([b"b", b"c", b"d"])
self.assertEqual(b"".join(a.stream), b"abcd")
def test_writeAfterClose(self):
"""
L{FakeTransport.write} will accept writes after transport was closed,
but the data will be silently discarded.
"""
a = FakeTransport(object(), False)
a.write(b"before")
a.loseConnection()
a.write(b"after")
self.assertEqual(b"".join(a.stream), b"before")
@implementer(IPushProducer)
class StrictPushProducer:
"""
An L{IPushProducer} implementation which produces nothing but enforces
preconditions on its state transition methods.
"""
_state = "running"
def stopProducing(self):
if self._state == "stopped":
raise ValueError("Cannot stop already-stopped IPushProducer")
self._state = "stopped"
def pauseProducing(self):
if self._state != "running":
raise ValueError(f"Cannot pause {self._state} IPushProducer")
self._state = "paused"
def resumeProducing(self):
if self._state != "paused":
raise ValueError(f"Cannot resume {self._state} IPushProducer")
self._state = "running"
class StrictPushProducerTests(TestCase):
"""
Tests for L{StrictPushProducer}.
"""
def _initial(self):
"""
@return: A new L{StrictPushProducer} which has not been through any state
changes.
"""
return StrictPushProducer()
def _stopped(self):
"""
@return: A new, stopped L{StrictPushProducer}.
"""
producer = StrictPushProducer()
producer.stopProducing()
return producer
def _paused(self):
"""
@return: A new, paused L{StrictPushProducer}.
"""
producer = StrictPushProducer()
producer.pauseProducing()
return producer
def _resumed(self):
"""
@return: A new L{StrictPushProducer} which has been paused and resumed.
"""
producer = StrictPushProducer()
producer.pauseProducing()
producer.resumeProducing()
return producer
def assertStopped(self, producer):
"""
Assert that the given producer is in the stopped state.
@param producer: The producer to verify.
@type producer: L{StrictPushProducer}
"""
self.assertEqual(producer._state, "stopped")
def assertPaused(self, producer):
"""
Assert that the given producer is in the paused state.
@param producer: The producer to verify.
@type producer: L{StrictPushProducer}
"""
self.assertEqual(producer._state, "paused")
def assertRunning(self, producer):
"""
Assert that the given producer is in the running state.
@param producer: The producer to verify.
@type producer: L{StrictPushProducer}
"""
self.assertEqual(producer._state, "running")
def test_stopThenStop(self):
"""
L{StrictPushProducer.stopProducing} raises L{ValueError} if called when
the producer is stopped.
"""
self.assertRaises(ValueError, self._stopped().stopProducing)
def test_stopThenPause(self):
"""
L{StrictPushProducer.pauseProducing} raises L{ValueError} if called when
the producer is stopped.
"""
self.assertRaises(ValueError, self._stopped().pauseProducing)
def test_stopThenResume(self):
"""
L{StrictPushProducer.resumeProducing} raises L{ValueError} if called when
the producer is stopped.
"""
self.assertRaises(ValueError, self._stopped().resumeProducing)
def test_pauseThenStop(self):
"""
L{StrictPushProducer} is stopped if C{stopProducing} is called on a paused
producer.
"""
producer = self._paused()
producer.stopProducing()
self.assertStopped(producer)
def test_pauseThenPause(self):
"""
L{StrictPushProducer.pauseProducing} raises L{ValueError} if called on a
paused producer.
"""
producer = self._paused()
self.assertRaises(ValueError, producer.pauseProducing)
def test_pauseThenResume(self):
"""
L{StrictPushProducer} is resumed if C{resumeProducing} is called on a
paused producer.
"""
producer = self._paused()
producer.resumeProducing()
self.assertRunning(producer)
def test_resumeThenStop(self):
"""
L{StrictPushProducer} is stopped if C{stopProducing} is called on a
resumed producer.
"""
producer = self._resumed()
producer.stopProducing()
self.assertStopped(producer)
def test_resumeThenPause(self):
"""
L{StrictPushProducer} is paused if C{pauseProducing} is called on a
resumed producer.
"""
producer = self._resumed()
producer.pauseProducing()
self.assertPaused(producer)
def test_resumeThenResume(self):
"""
L{StrictPushProducer.resumeProducing} raises L{ValueError} if called on a
resumed producer.
"""
producer = self._resumed()
self.assertRaises(ValueError, producer.resumeProducing)
def test_stop(self):
"""
L{StrictPushProducer} is stopped if C{stopProducing} is called in the
initial state.
"""
producer = self._initial()
producer.stopProducing()
self.assertStopped(producer)
def test_pause(self):
"""
L{StrictPushProducer} is paused if C{pauseProducing} is called in the
initial state.
"""
producer = self._initial()
producer.pauseProducing()
self.assertPaused(producer)
def test_resume(self):
"""
L{StrictPushProducer} raises L{ValueError} if C{resumeProducing} is called
in the initial state.
"""
producer = self._initial()
self.assertRaises(ValueError, producer.resumeProducing)
class IOPumpTests(TestCase):
"""
Tests for L{IOPump}.
"""
def _testStreamingProducer(self, mode):
"""
Connect a couple protocol/transport pairs to an L{IOPump} and then pump
it. Verify that a streaming producer registered with one of the
transports does not receive invalid L{IPushProducer} method calls and
ends in the right state.
@param mode: C{u"server"} to test a producer registered with the
server transport. C{u"client"} to test a producer registered with
the client transport.
"""
serverProto = Protocol()
serverTransport = FakeTransport(serverProto, isServer=True)
clientProto = Protocol()
clientTransport = FakeTransport(clientProto, isServer=False)
pump = connect(
serverProto,
serverTransport,
clientProto,
clientTransport,
greet=False,
)
producer = StrictPushProducer()
victim = {
"server": serverTransport,
"client": clientTransport,
}[mode]
victim.registerProducer(producer, streaming=True)
pump.pump()
self.assertEqual("running", producer._state)
def test_serverStreamingProducer(self):
"""
L{IOPump.pump} does not call C{resumeProducing} on a L{IPushProducer}
(stream producer) registered with the server transport.
"""
self._testStreamingProducer(mode="server")
def test_clientStreamingProducer(self):
"""
L{IOPump.pump} does not call C{resumeProducing} on a L{IPushProducer}
(stream producer) registered with the client transport.
"""
self._testStreamingProducer(mode="client")
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