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

"""
Tests for L{twisted.runner.procmon}.
"""
from __future__ import annotations

import errno
import os
import pickle
from typing import AnyStr, Mapping, Optional, Sequence, Union

from zope.interface import implementer

from twisted.internet.error import ProcessDone, ProcessExitedAlready, ProcessTerminated
from twisted.internet.interfaces import IProcessProtocol, IProcessTransport
from twisted.internet.task import Clock
from twisted.internet.testing import MemoryReactor
from twisted.logger import globalLogPublisher
from twisted.python.failure import Failure
from twisted.runner.procmon import LoggingProtocol, ProcessMonitor
from twisted.trial import unittest


@implementer(IProcessTransport)
class DummyProcess:  # type:ignore[misc]
    """
    An incomplete and fake L{IProcessTransport} implementation for testing how
    L{ProcessMonitor} behaves when its monitored processes exit.

    @ivar _terminationDelay: the delay in seconds after which the DummyProcess
        will appear to exit when it receives a TERM signal
    """

    pid = 1
    proto = None

    _terminationDelay = 1

    def __init__(
        self,
        reactor,
        executable,
        args,
        environment,
        path,
        proto,
        uid=None,
        gid=None,
        usePTY=0,
        childFDs=None,
    ):
        self.proto = proto

        self._reactor = reactor
        self._executable = executable
        self._args = args
        self._environment = environment
        self._path = path
        self._uid = uid
        self._gid = gid
        self._usePTY = usePTY
        self._childFDs = childFDs

    def signalProcess(self, signalID):
        """
        A partial implementation of signalProcess which can only handle TERM and
        KILL signals.
         - When a TERM signal is given, the dummy process will appear to exit
           after L{DummyProcess._terminationDelay} seconds with exit code 0
         - When a KILL signal is given, the dummy process will appear to exit
           immediately with exit code 1.

        @param signalID: The signal name or number to be issued to the process.
        @type signalID: C{str}
        """
        params = {"TERM": (self._terminationDelay, 0), "KILL": (0, 1)}

        if self.pid is None:
            raise ProcessExitedAlready()

        if signalID in params:
            delay, status = params[signalID]
            self._signalHandler = self._reactor.callLater(
                delay, self.processEnded, status
            )

    def processEnded(self, status):
        """
        Deliver the process ended event to C{self.proto}.
        """
        self.pid = None
        statusMap = {
            0: ProcessDone,
            1: ProcessTerminated,
        }
        self.proto.processEnded(Failure(statusMap[status](status)))


class DummyProcessReactor(MemoryReactor, Clock):
    """
    @ivar spawnedProcesses: a list that keeps track of the fake process
        instances built by C{spawnProcess}.

    @ivar spawnProcessException: An exception which spawnProcess() will raise.
    """

    spawnedProcesses: list[DummyProcess]
    spawnProcessException: Exception | None

    def __init__(self) -> None:
        MemoryReactor.__init__(self)
        Clock.__init__(self)
        self.spawnedProcesses = []
        self.spawnProcessException = None

    def spawnProcess(
        self,
        processProtocol: IProcessProtocol,
        executable: Union[bytes, str],
        args: Sequence[Union[bytes, str]],
        env: Optional[Mapping[AnyStr, AnyStr]] = None,
        path: Union[None, bytes, str] = None,
        uid: Optional[int] = None,
        gid: Optional[int] = None,
        usePTY: bool = False,
        childFDs: Optional[Mapping[int, Union[int, str]]] = None,
    ) -> IProcessTransport:
        """
        Fake L{reactor.spawnProcess}, that logs all the process
        arguments and returns a L{DummyProcess}.
        """
        if self.spawnProcessException is not None:
            raise self.spawnProcessException

        proc = DummyProcess(
            self,
            executable,
            args,
            env,
            path,
            processProtocol,
            uid,
            gid,
            usePTY,
            childFDs,
        )
        processProtocol.makeConnection(proc)
        self.spawnedProcesses.append(proc)
        return proc


class ProcmonTests(unittest.TestCase):
    """
    Tests for L{ProcessMonitor}.
    """

    def setUp(self):
        """
        Create an L{ProcessMonitor} wrapped around a fake reactor.
        """
        self.reactor = DummyProcessReactor()
        self.pm = ProcessMonitor(reactor=self.reactor)
        self.pm.minRestartDelay = 2
        self.pm.maxRestartDelay = 10
        self.pm.threshold = 10

    def test_reprLooksGood(self):
        """
        Repr includes all details
        """
        self.pm.addProcess("foo", ["arg1", "arg2"], uid=1, gid=2, env={})
        representation = repr(self.pm)
        self.assertIn("foo", representation)
        self.assertIn("1", representation)
        self.assertIn("2", representation)

    def test_simpleReprLooksGood(self):
        """
        Repr does not include unneeded details.

        Values of attributes that just mean "inherit from launching
        process" do not appear in the repr of a process.
        """
        self.pm.addProcess("foo", ["arg1", "arg2"], env={})
        representation = repr(self.pm)
        self.assertNotIn("(", representation)
        self.assertNotIn(")", representation)

    def test_getStateIncludesProcesses(self):
        """
        The list of monitored processes must be included in the pickle state.
        """
        self.pm.addProcess("foo", ["arg1", "arg2"], uid=1, gid=2, env={})
        self.assertEqual(
            self.pm.__getstate__()["processes"], {"foo": (["arg1", "arg2"], 1, 2, {})}
        )

    def test_getStateExcludesReactor(self):
        """
        The private L{ProcessMonitor._reactor} instance variable should not be
        included in the pickle state.
        """
        self.assertNotIn("_reactor", self.pm.__getstate__())

    def test_addProcess(self):
        """
        L{ProcessMonitor.addProcess} only starts the named program if
        L{ProcessMonitor.startService} has been called.
        """
        self.pm.addProcess("foo", ["arg1", "arg2"], uid=1, gid=2, env={})
        self.assertEqual(self.pm.protocols, {})
        self.assertEqual(self.pm.processes, {"foo": (["arg1", "arg2"], 1, 2, {})})
        self.pm.startService()
        self.reactor.advance(0)
        self.assertEqual(list(self.pm.protocols.keys()), ["foo"])

    def test_addProcessDuplicateKeyError(self):
        """
        L{ProcessMonitor.addProcess} raises a C{KeyError} if a process with the
        given name already exists.
        """
        self.pm.addProcess("foo", ["arg1", "arg2"], uid=1, gid=2, env={})
        self.assertRaises(
            KeyError, self.pm.addProcess, "foo", ["arg1", "arg2"], uid=1, gid=2, env={}
        )

    def test_addProcessEnv(self):
        """
        L{ProcessMonitor.addProcess} takes an C{env} parameter that is passed to
        L{IReactorProcess.spawnProcess}.
        """
        fakeEnv = {"KEY": "value"}
        self.pm.startService()
        self.pm.addProcess("foo", ["foo"], uid=1, gid=2, env=fakeEnv)
        self.reactor.advance(0)
        self.assertEqual(self.reactor.spawnedProcesses[0]._environment, fakeEnv)

    def test_addProcessCwd(self):
        """
        L{ProcessMonitor.addProcess} takes an C{cwd} parameter that is passed
        to L{IReactorProcess.spawnProcess}.
        """
        self.pm.startService()
        self.pm.addProcess("foo", ["foo"], cwd="/mnt/lala")
        self.reactor.advance(0)
        self.assertEqual(self.reactor.spawnedProcesses[0]._path, "/mnt/lala")

    def test_removeProcess(self):
        """
        L{ProcessMonitor.removeProcess} removes the process from the public
        processes list.
        """
        self.pm.startService()
        self.pm.addProcess("foo", ["foo"])
        self.assertEqual(len(self.pm.processes), 1)
        self.pm.removeProcess("foo")
        self.assertEqual(len(self.pm.processes), 0)

    def test_removeProcessUnknownKeyError(self):
        """
        L{ProcessMonitor.removeProcess} raises a C{KeyError} if the given
        process name isn't recognised.
        """
        self.pm.startService()
        self.assertRaises(KeyError, self.pm.removeProcess, "foo")

    def test_startProcess(self):
        """
        When a process has been started, an instance of L{LoggingProtocol} will
        be added to the L{ProcessMonitor.protocols} dict and the start time of
        the process will be recorded in the L{ProcessMonitor.timeStarted}
        dictionary.
        """
        self.pm.addProcess("foo", ["foo"])
        self.pm.startProcess("foo")
        self.assertIsInstance(self.pm.protocols["foo"], LoggingProtocol)
        self.assertIn("foo", self.pm.timeStarted.keys())

    def test_startProcessAlreadyStarted(self):
        """
        L{ProcessMonitor.startProcess} silently returns if the named process is
        already started.
        """
        self.pm.addProcess("foo", ["foo"])
        self.pm.startProcess("foo")
        self.assertIsNone(self.pm.startProcess("foo"))

    def test_startProcessUnknownKeyError(self):
        """
        L{ProcessMonitor.startProcess} raises a C{KeyError} if the given
        process name isn't recognised.
        """
        self.assertRaises(KeyError, self.pm.startProcess, "foo")

    def test_startProcessSpawnCaughtException(self) -> None:
        """
        L{IReactorProcess.spawnProcess} might raise C{OSError}, ensure it
        is caught and process is restarted.
        """
        self.reactor.spawnProcessException = OSError(
            errno.EAGAIN, os.strerror(errno.EAGAIN)
        )
        self.pm.minRestartDelay = 123
        self.pm.maxRestartDelay = 123
        self.pm.addProcess("foo", ["foo"])
        self.pm.startProcess("foo")
        # process will be restarted in 123 seconds, per minRestartDelay and maxRestartDelay above
        self.assertEqual(self.pm.delay["foo"], 123)
        self.assertEqual(len(self.flushLoggedErrors(OSError)), 1)

    def test_startProcessSpawnUncaughtException(self) -> None:
        """
        L{IReactorProcess.spawnProcess} might raise C{OSError}, ensure other
        exceptions are not caught.
        """
        self.reactor.spawnProcessException = SystemError("Just another exception")
        self.pm.addProcess("foo", ["foo"])
        self.assertRaises(SystemError, self.pm.startProcess, "foo")

    def test_stopProcessNaturalTermination(self):
        """
        L{ProcessMonitor.stopProcess} immediately sends a TERM signal to the
        named process.
        """
        self.pm.startService()
        self.pm.addProcess("foo", ["foo"])
        self.assertIn("foo", self.pm.protocols)

        # Configure fake process to die 1 second after receiving term signal
        timeToDie = self.pm.protocols["foo"].transport._terminationDelay = 1

        # Advance the reactor to just before the short lived process threshold
        # and leave enough time for the process to die
        self.reactor.advance(self.pm.threshold)
        # Then signal the process to stop
        self.pm.stopProcess("foo")

        # Advance the reactor just enough to give the process time to die and
        # verify that the process restarts
        self.reactor.advance(timeToDie)

        # No further time is required to pass here but the reactor must
        # iterate due to implementation details.  See the comment in
        # test_stopProcessForcedKill.
        self.reactor.advance(0)

        # We expect it to be restarted immediately
        self.assertEqual(self.reactor.seconds(), self.pm.timeStarted["foo"])

    def test_stopProcessForcedKill(self):
        """
        L{ProcessMonitor.stopProcess} kills a process which fails to terminate
        naturally within L{ProcessMonitor.killTime} seconds.
        """
        self.pm.startService()
        self.pm.addProcess("foo", ["foo"])
        self.assertIn("foo", self.pm.protocols)
        self.reactor.advance(self.pm.threshold)
        proc = self.pm.protocols["foo"].transport
        # Arrange for the fake process to live longer than the killTime
        proc._terminationDelay = self.pm.killTime + 1
        self.pm.stopProcess("foo")
        # If process doesn't die before the killTime, procmon should
        # terminate it
        self.reactor.advance(self.pm.killTime - 1)
        self.assertEqual(0.0, self.pm.timeStarted["foo"])

        self.reactor.advance(1)

        # We expect it to be immediately restarted.  While no actual time
        # should need to pass for this to happen, the reactor will need to
        # iterate a couple times because the implementation uses `callLater`
        # (twice!) to schedule the restart and no delayed call can run sooner
        # than the reactor iteration after it is scheduled.
        self.reactor.pump([0, 0])

        self.assertEqual(self.reactor.seconds(), self.pm.timeStarted["foo"])

    def test_stopProcessUnknownKeyError(self):
        """
        L{ProcessMonitor.stopProcess} raises a C{KeyError} if the given process
        name isn't recognised.
        """
        self.assertRaises(KeyError, self.pm.stopProcess, "foo")

    def test_stopProcessAlreadyStopped(self):
        """
        L{ProcessMonitor.stopProcess} silently returns if the named process
        is already stopped. eg Process has crashed and a restart has been
        rescheduled, but in the meantime, the service is stopped.
        """
        self.pm.addProcess("foo", ["foo"])
        self.assertIsNone(self.pm.stopProcess("foo"))

    def test_outputReceivedCompleteLine(self):
        """
        Getting a complete output line on stdout generates a log message.
        """
        events = []
        self.addCleanup(globalLogPublisher.removeObserver, events.append)
        globalLogPublisher.addObserver(events.append)
        self.pm.addProcess("foo", ["foo"])
        # Schedule the process to start
        self.pm.startService()
        # Advance the reactor to start the process
        self.reactor.advance(0)
        self.assertIn("foo", self.pm.protocols)
        # Long time passes
        self.reactor.advance(self.pm.threshold)
        # Process greets
        self.pm.protocols["foo"].outReceived(b"hello world!\n")
        self.assertEqual(len(events), 1)
        namespace = events[0]["log_namespace"]
        stream = events[0]["stream"]
        tag = events[0]["tag"]
        line = events[0]["line"]
        self.assertEqual(namespace, "twisted.runner.procmon.ProcessMonitor")
        self.assertEqual(stream, "stdout")
        self.assertEqual(tag, "foo")
        self.assertEqual(line, "hello world!")

    def test_outputReceivedCompleteErrLine(self):
        """
        Getting a complete output line on stderr generates a log message.
        """
        events = []
        self.addCleanup(globalLogPublisher.removeObserver, events.append)
        globalLogPublisher.addObserver(events.append)
        self.pm.addProcess("foo", ["foo"])
        # Schedule the process to start
        self.pm.startService()
        # Advance the reactor to start the process
        self.reactor.advance(0)
        self.assertIn("foo", self.pm.protocols)
        # Long time passes
        self.reactor.advance(self.pm.threshold)
        # Process greets
        self.pm.protocols["foo"].errReceived(b"hello world!\n")
        self.assertEqual(len(events), 1)
        namespace = events[0]["log_namespace"]
        stream = events[0]["stream"]
        tag = events[0]["tag"]
        line = events[0]["line"]
        self.assertEqual(namespace, "twisted.runner.procmon.ProcessMonitor")
        self.assertEqual(stream, "stderr")
        self.assertEqual(tag, "foo")
        self.assertEqual(line, "hello world!")

    def test_outputReceivedCompleteLineInvalidUTF8(self):
        """
        Getting invalid UTF-8 results in the repr of the raw message
        """
        events = []
        self.addCleanup(globalLogPublisher.removeObserver, events.append)
        globalLogPublisher.addObserver(events.append)
        self.pm.addProcess("foo", ["foo"])
        # Schedule the process to start
        self.pm.startService()
        # Advance the reactor to start the process
        self.reactor.advance(0)
        self.assertIn("foo", self.pm.protocols)
        # Long time passes
        self.reactor.advance(self.pm.threshold)
        # Process greets
        self.pm.protocols["foo"].outReceived(b"\xffhello world!\n")
        self.assertEqual(len(events), 1)
        message = events[0]
        namespace = message["log_namespace"]
        stream = message["stream"]
        tag = message["tag"]
        output = message["line"]
        self.assertEqual(namespace, "twisted.runner.procmon.ProcessMonitor")
        self.assertEqual(stream, "stdout")
        self.assertEqual(tag, "foo")
        self.assertEqual(output, repr(b"\xffhello world!"))

    def test_outputReceivedPartialLine(self):
        """
        Getting partial line results in no events until process end
        """
        events = []
        self.addCleanup(globalLogPublisher.removeObserver, events.append)
        globalLogPublisher.addObserver(events.append)
        self.pm.addProcess("foo", ["foo"])
        # Schedule the process to start
        self.pm.startService()
        # Advance the reactor to start the process
        self.reactor.advance(0)
        self.assertIn("foo", self.pm.protocols)
        # Long time passes
        self.reactor.advance(self.pm.threshold)
        # Process greets
        self.pm.protocols["foo"].outReceived(b"hello world!")
        self.assertEqual(len(events), 0)
        self.pm.protocols["foo"].processEnded(Failure(ProcessDone(0)))
        self.assertEqual(len(events), 1)
        namespace = events[0]["log_namespace"]
        stream = events[0]["stream"]
        tag = events[0]["tag"]
        line = events[0]["line"]
        self.assertEqual(namespace, "twisted.runner.procmon.ProcessMonitor")
        self.assertEqual(stream, "stdout")
        self.assertEqual(tag, "foo")
        self.assertEqual(line, "hello world!")

    def test_connectionLostLongLivedProcess(self):
        """
        L{ProcessMonitor.processExit} should immediately restart a process
        if it has been running longer than L{ProcessMonitor.threshold} seconds.
        """
        self.pm.addProcess("foo", ["foo"])
        # Schedule the process to start
        self.pm.startService()
        # advance the reactor to start the process
        self.reactor.advance(0)
        self.assertIn("foo", self.pm.protocols)
        # Long time passes
        self.reactor.advance(self.pm.threshold)
        # Process dies after threshold
        self.pm.protocols["foo"].processEnded(Failure(ProcessDone(0)))
        self.assertNotIn("foo", self.pm.protocols)
        # Process should be restarted immediately
        self.reactor.advance(0)
        self.assertIn("foo", self.pm.protocols)

    def test_connectionLostMurderCancel(self):
        """
        L{ProcessMonitor.processExit} cancels a scheduled process killer and
        deletes the DelayedCall from the L{ProcessMonitor.murder} list.
        """
        self.pm.addProcess("foo", ["foo"])
        # Schedule the process to start
        self.pm.startService()
        # Advance 1s to start the process then ask ProcMon to stop it
        self.reactor.advance(1)
        self.pm.stopProcess("foo")
        # A process killer has been scheduled, delayedCall is active
        self.assertIn("foo", self.pm.murder)
        delayedCall = self.pm.murder["foo"]
        self.assertTrue(delayedCall.active())
        # Advance to the point at which the dummy process exits
        self.reactor.advance(self.pm.protocols["foo"].transport._terminationDelay)
        # Now the delayedCall has been cancelled and deleted
        self.assertFalse(delayedCall.active())
        self.assertNotIn("foo", self.pm.murder)

    def test_connectionLostProtocolDeletion(self):
        """
        L{ProcessMonitor.processExit} removes the corresponding
        ProcessProtocol instance from the L{ProcessMonitor.protocols} list.
        """
        self.pm.startService()
        self.pm.addProcess("foo", ["foo"])
        self.assertIn("foo", self.pm.protocols)
        self.pm.protocols["foo"].transport.signalProcess("KILL")
        self.reactor.advance(self.pm.protocols["foo"].transport._terminationDelay)
        self.assertNotIn("foo", self.pm.protocols)

    def test_connectionLostMinMaxRestartDelay(self):
        """
        L{ProcessMonitor.processExit} will wait at least minRestartDelay s
        and at most maxRestartDelay s
        """
        self.pm.minRestartDelay = 2
        self.pm.maxRestartDelay = 3

        self.pm.startService()
        self.pm.addProcess("foo", ["foo"])

        self.assertEqual(self.pm.delay["foo"], self.pm.minRestartDelay)
        self.reactor.advance(self.pm.threshold - 1)
        self.pm.protocols["foo"].processEnded(Failure(ProcessDone(0)))
        self.assertEqual(self.pm.delay["foo"], self.pm.maxRestartDelay)

    def test_connectionLostBackoffDelayDoubles(self):
        """
        L{ProcessMonitor.processExit} doubles the restart delay each time
        the process dies too quickly.
        """
        self.pm.startService()
        self.pm.addProcess("foo", ["foo"])
        self.reactor.advance(self.pm.threshold - 1)  # 9s
        self.assertIn("foo", self.pm.protocols)
        self.assertEqual(self.pm.delay["foo"], self.pm.minRestartDelay)
        # process dies within the threshold and should not restart immediately
        self.pm.protocols["foo"].processEnded(Failure(ProcessDone(0)))
        self.assertEqual(self.pm.delay["foo"], self.pm.minRestartDelay * 2)

    def test_startService(self):
        """
        L{ProcessMonitor.startService} starts all monitored processes.
        """
        self.pm.addProcess("foo", ["foo"])
        # Schedule the process to start
        self.pm.startService()
        # advance the reactor to start the process
        self.reactor.advance(0)
        self.assertIn("foo", self.pm.protocols)

    def test_stopService(self):
        """
        L{ProcessMonitor.stopService} should stop all monitored processes.
        """
        self.pm.addProcess("foo", ["foo"])
        self.pm.addProcess("bar", ["bar"])
        # Schedule the process to start
        self.pm.startService()
        # advance the reactor to start the processes
        self.reactor.advance(self.pm.threshold)
        self.assertIn("foo", self.pm.protocols)
        self.assertIn("bar", self.pm.protocols)

        self.reactor.advance(1)

        self.pm.stopService()
        # Advance to beyond the killTime - all monitored processes
        # should have exited
        self.reactor.advance(self.pm.killTime + 1)
        # The processes shouldn't be restarted
        self.assertEqual({}, self.pm.protocols)

    def test_restartAllRestartsOneProcess(self):
        """
        L{ProcessMonitor.restartAll} succeeds when there is one process.
        """
        self.pm.addProcess("foo", ["foo"])
        self.pm.startService()
        self.reactor.advance(1)
        self.pm.restartAll()
        # Just enough time for the process to die,
        # not enough time to start a new one.
        self.reactor.advance(1)
        processes = list(self.reactor.spawnedProcesses)
        myProcess = processes.pop()
        self.assertEqual(processes, [])
        self.assertIsNone(myProcess.pid)

    def test_stopServiceCancelRestarts(self):
        """
        L{ProcessMonitor.stopService} should cancel any scheduled process
        restarts.
        """
        self.pm.addProcess("foo", ["foo"])
        # Schedule the process to start
        self.pm.startService()
        # advance the reactor to start the processes
        self.reactor.advance(self.pm.threshold)
        self.assertIn("foo", self.pm.protocols)

        self.reactor.advance(1)
        # Kill the process early
        self.pm.protocols["foo"].processEnded(Failure(ProcessDone(0)))
        self.assertTrue(self.pm.restart["foo"].active())
        self.pm.stopService()
        # Scheduled restart should have been cancelled
        self.assertFalse(self.pm.restart["foo"].active())

    def test_stopServiceCleanupScheduledRestarts(self):
        """
        L{ProcessMonitor.stopService} should cancel all scheduled process
        restarts.
        """
        self.pm.threshold = 5
        self.pm.minRestartDelay = 5
        # Start service and add a process (started immediately)
        self.pm.startService()
        self.pm.addProcess("foo", ["foo"])
        # Stop the process after 1s
        self.reactor.advance(1)
        self.pm.stopProcess("foo")
        # Wait 1s for it to exit it will be scheduled to restart 5s later
        self.reactor.advance(1)
        # Meanwhile stop the service
        self.pm.stopService()
        # Advance to beyond the process restart time
        self.reactor.advance(6)
        # The process shouldn't have restarted because stopService has cancelled
        # all pending process restarts.
        self.assertEqual(self.pm.protocols, {})


class DeprecationTests(unittest.SynchronousTestCase):
    """
    Tests that check functionality that should be deprecated is deprecated.
    """

    def setUp(self):
        """
        Create reactor and process monitor.
        """
        self.reactor = DummyProcessReactor()
        self.pm = ProcessMonitor(reactor=self.reactor)

    def test_toTuple(self):
        """
        _Process.toTuple is deprecated.

        When getting the deprecated processes property, the actual
        data (kept in the class _Process) is converted to a tuple --
        which produces a DeprecationWarning per process so converted.
        """
        self.pm.addProcess("foo", ["foo"])
        myprocesses = self.pm.processes
        self.assertEqual(len(myprocesses), 1)
        warnings = self.flushWarnings()
        foundToTuple = False
        for warning in warnings:
            self.assertIs(warning["category"], DeprecationWarning)
            if "toTuple" in warning["message"]:
                foundToTuple = True
        self.assertTrue(foundToTuple, f"no tuple deprecation found:{repr(warnings)}")

    def test_processes(self):
        """
        Accessing L{ProcessMonitor.processes} results in deprecation warning

        Even when there are no processes, and thus no process is converted
        to a tuple, accessing the L{ProcessMonitor.processes} property
        should generate its own DeprecationWarning.
        """
        myProcesses = self.pm.processes
        self.assertEqual(myProcesses, {})
        warnings = self.flushWarnings()
        first = warnings.pop(0)
        self.assertIs(first["category"], DeprecationWarning)
        self.assertEqual(warnings, [])

    def test_getstate(self):
        """
        Pickling an L{ProcessMonitor} results in deprecation warnings
        """
        pickle.dumps(self.pm)
        warnings = self.flushWarnings()
        for warning in warnings:
            self.assertIs(warning["category"], DeprecationWarning)
