test_unix_events.py

"""Tests for unix_events.py."""

import contextlib
import errno
import io
import multiprocessing
from multiprocessing.util import _cleanup_tests as multiprocessing_cleanup_tests
import os
import pathlib
import signal
import socket
import stat
import sys
import threading
import time
import unittest
from unittest import mock
import warnings

from test import support
from test.support import os_helper
from test.support import socket_helper
from test.support import wait_process
from test.support import hashlib_helper

if sys.platform == 'win32':
    raise unittest.SkipTest('UNIX only')


import asyncio
from asyncio import log
from asyncio import unix_events
from test.test_asyncio import utils as test_utils


def tearDownModule():
    asyncio.set_event_loop_policy(None)


MOCK_ANY = mock.ANY


def EXITCODE(exitcode):
    return 32768 + exitcode


def SIGNAL(signum):
    if not 1 <= signum <= 68:
        raise AssertionError(f'invalid signum {signum}')
    return 32768 - signum


def close_pipe_transport(transport):
    # Don't call transport.close() because the event loop and the selector
    # are mocked
    if transport._pipe is None:
        return
    transport._pipe.close()
    transport._pipe = None


@unittest.skipUnless(signal, 'Signals are not supported')
class SelectorEventLoopSignalTests(test_utils.TestCase):

    def setUp(self):
        super().setUp()
        self.loop = asyncio.SelectorEventLoop()
        self.set_event_loop(self.loop)

    def test_check_signal(self):
        self.assertRaises(
            TypeError, self.loop._check_signal, '1')
        self.assertRaises(
            ValueError, self.loop._check_signal, signal.NSIG + 1)

    def test_handle_signal_no_handler(self):
        self.loop._handle_signal(signal.NSIG + 1)

    def test_handle_signal_cancelled_handler(self):
        h = asyncio.Handle(mock.Mock(), (),
                           loop=mock.Mock())
        h.cancel()
        self.loop._signal_handlers[signal.NSIG + 1] = h
        self.loop.remove_signal_handler = mock.Mock()
        self.loop._handle_signal(signal.NSIG + 1)
        self.loop.remove_signal_handler.assert_called_with(signal.NSIG + 1)

    @mock.patch('asyncio.unix_events.signal')
    def test_add_signal_handler_setup_error(self, m_signal):
        m_signal.NSIG = signal.NSIG
        m_signal.valid_signals = signal.valid_signals
        m_signal.set_wakeup_fd.side_effect = ValueError

        self.assertRaises(
            RuntimeError,
            self.loop.add_signal_handler,
            signal.SIGINT, lambda: True)

    @mock.patch('asyncio.unix_events.signal')
    def test_add_signal_handler_coroutine_error(self, m_signal):
        m_signal.NSIG = signal.NSIG

        async def simple_coroutine():
            pass

        # callback must not be a coroutine function
        coro_func = simple_coroutine
        coro_obj = coro_func()
        self.addCleanup(coro_obj.close)
        for func in (coro_func, coro_obj):
            self.assertRaisesRegex(
                TypeError, 'coroutines cannot be used with add_signal_handler',
                self.loop.add_signal_handler,
                signal.SIGINT, func)

    @mock.patch('asyncio.unix_events.signal')
    def test_add_signal_handler(self, m_signal):
        m_signal.NSIG = signal.NSIG
        m_signal.valid_signals = signal.valid_signals

        cb = lambda: True
        self.loop.add_signal_handler(signal.SIGHUP, cb)
        h = self.loop._signal_handlers.get(signal.SIGHUP)
        self.assertIsInstance(h, asyncio.Handle)
        self.assertEqual(h._callback, cb)

    @mock.patch('asyncio.unix_events.signal')
    def test_add_signal_handler_install_error(self, m_signal):
        m_signal.NSIG = signal.NSIG
        m_signal.valid_signals = signal.valid_signals

        def set_wakeup_fd(fd):
            if fd == -1:
                raise ValueError()
        m_signal.set_wakeup_fd = set_wakeup_fd

        class Err(OSError):
            errno = errno.EFAULT
        m_signal.signal.side_effect = Err

        self.assertRaises(
            Err,
            self.loop.add_signal_handler,
            signal.SIGINT, lambda: True)

    @mock.patch('asyncio.unix_events.signal')
    @mock.patch('asyncio.base_events.logger')
    def test_add_signal_handler_install_error2(self, m_logging, m_signal):
        m_signal.NSIG = signal.NSIG
        m_signal.valid_signals = signal.valid_signals

        class Err(OSError):
            errno = errno.EINVAL
        m_signal.signal.side_effect = Err

        self.loop._signal_handlers[signal.SIGHUP] = lambda: True
        self.assertRaises(
            RuntimeError,
            self.loop.add_signal_handler,
            signal.SIGINT, lambda: True)
        self.assertFalse(m_logging.info.called)
        self.assertEqual(1, m_signal.set_wakeup_fd.call_count)

    @mock.patch('asyncio.unix_events.signal')
    @mock.patch('asyncio.base_events.logger')
    def test_add_signal_handler_install_error3(self, m_logging, m_signal):
        class Err(OSError):
            errno = errno.EINVAL
        m_signal.signal.side_effect = Err
        m_signal.NSIG = signal.NSIG
        m_signal.valid_signals = signal.valid_signals

        self.assertRaises(
            RuntimeError,
            self.loop.add_signal_handler,
            signal.SIGINT, lambda: True)
        self.assertFalse(m_logging.info.called)
        self.assertEqual(2, m_signal.set_wakeup_fd.call_count)

    @mock.patch('asyncio.unix_events.signal')
    def test_remove_signal_handler(self, m_signal):
        m_signal.NSIG = signal.NSIG
        m_signal.valid_signals = signal.valid_signals

        self.loop.add_signal_handler(signal.SIGHUP, lambda: True)

        self.assertTrue(
            self.loop.remove_signal_handler(signal.SIGHUP))
        self.assertTrue(m_signal.set_wakeup_fd.called)
        self.assertTrue(m_signal.signal.called)
        self.assertEqual(
            (signal.SIGHUP, m_signal.SIG_DFL), m_signal.signal.call_args[0])

    @mock.patch('asyncio.unix_events.signal')
    def test_remove_signal_handler_2(self, m_signal):
        m_signal.NSIG = signal.NSIG
        m_signal.SIGINT = signal.SIGINT
        m_signal.valid_signals = signal.valid_signals

        self.loop.add_signal_handler(signal.SIGINT, lambda: True)
        self.loop._signal_handlers[signal.SIGHUP] = object()
        m_signal.set_wakeup_fd.reset_mock()

        self.assertTrue(
            self.loop.remove_signal_handler(signal.SIGINT))
        self.assertFalse(m_signal.set_wakeup_fd.called)
        self.assertTrue(m_signal.signal.called)
        self.assertEqual(
            (signal.SIGINT, m_signal.default_int_handler),
            m_signal.signal.call_args[0])

    @mock.patch('asyncio.unix_events.signal')
    @mock.patch('asyncio.base_events.logger')
    def test_remove_signal_handler_cleanup_error(self, m_logging, m_signal):
        m_signal.NSIG = signal.NSIG
        m_signal.valid_signals = signal.valid_signals
        self.loop.add_signal_handler(signal.SIGHUP, lambda: True)

        m_signal.set_wakeup_fd.side_effect = ValueError

        self.loop.remove_signal_handler(signal.SIGHUP)
        self.assertTrue(m_logging.info)

    @mock.patch('asyncio.unix_events.signal')
    def test_remove_signal_handler_error(self, m_signal):
        m_signal.NSIG = signal.NSIG
        m_signal.valid_signals = signal.valid_signals
        self.loop.add_signal_handler(signal.SIGHUP, lambda: True)

        m_signal.signal.side_effect = OSError

        self.assertRaises(
            OSError, self.loop.remove_signal_handler, signal.SIGHUP)

    @mock.patch('asyncio.unix_events.signal')
    def test_remove_signal_handler_error2(self, m_signal):
        m_signal.NSIG = signal.NSIG
        m_signal.valid_signals = signal.valid_signals
        self.loop.add_signal_handler(signal.SIGHUP, lambda: True)

        class Err(OSError):
            errno = errno.EINVAL
        m_signal.signal.side_effect = Err

        self.assertRaises(
            RuntimeError, self.loop.remove_signal_handler, signal.SIGHUP)

    @mock.patch('asyncio.unix_events.signal')
    def test_close(self, m_signal):
        m_signal.NSIG = signal.NSIG
        m_signal.valid_signals = signal.valid_signals

        self.loop.add_signal_handler(signal.SIGHUP, lambda: True)
        self.loop.add_signal_handler(signal.SIGCHLD, lambda: True)

        self.assertEqual(len(self.loop._signal_handlers), 2)

        m_signal.set_wakeup_fd.reset_mock()

        self.loop.close()

        self.assertEqual(len(self.loop._signal_handlers), 0)
        m_signal.set_wakeup_fd.assert_called_once_with(-1)

    @mock.patch('asyncio.unix_events.sys')
    @mock.patch('asyncio.unix_events.signal')
    def test_close_on_finalizing(self, m_signal, m_sys):
        m_signal.NSIG = signal.NSIG
        m_signal.valid_signals = signal.valid_signals
        self.loop.add_signal_handler(signal.SIGHUP, lambda: True)

        self.assertEqual(len(self.loop._signal_handlers), 1)
        m_sys.is_finalizing.return_value = True
        m_signal.signal.reset_mock()

        with self.assertWarnsRegex(ResourceWarning,
                                   "skipping signal handlers removal"):
            self.loop.close()

        self.assertEqual(len(self.loop._signal_handlers), 0)
        self.assertFalse(m_signal.signal.called)


@unittest.skipUnless(hasattr(socket, 'AF_UNIX'),
                     'UNIX Sockets are not supported')
class SelectorEventLoopUnixSocketTests(test_utils.TestCase):

    def setUp(self):
        super().setUp()
        self.loop = asyncio.SelectorEventLoop()
        self.set_event_loop(self.loop)

    @socket_helper.skip_unless_bind_unix_socket
    def test_create_unix_server_existing_path_sock(self):
        with test_utils.unix_socket_path() as path:
            sock = socket.socket(socket.AF_UNIX)
            sock.bind(path)
            sock.listen(1)
            sock.close()

            coro = self.loop.create_unix_server(lambda: None, path)
            srv = self.loop.run_until_complete(coro)
            srv.close()
            self.loop.run_until_complete(srv.wait_closed())

    @socket_helper.skip_unless_bind_unix_socket
    def test_create_unix_server_pathlib(self):
        with test_utils.unix_socket_path() as path:
            path = pathlib.Path(path)
            srv_coro = self.loop.create_unix_server(lambda: None, path)
            srv = self.loop.run_until_complete(srv_coro)
            srv.close()
            self.loop.run_until_complete(srv.wait_closed())

    def test_create_unix_connection_pathlib(self):
        with test_utils.unix_socket_path() as path:
            path = pathlib.Path(path)
            coro = self.loop.create_unix_connection(lambda: None, path)
            with self.assertRaises(FileNotFoundError):
                # If pathlib.Path wasn't supported, the exception would be
                # different.
                self.loop.run_until_complete(coro)

    def test_create_unix_server_existing_path_nonsock(self):
        path = test_utils.gen_unix_socket_path()
        self.addCleanup(os_helper.unlink, path)
        # create the file
        open(path, "wb").close()

        coro = self.loop.create_unix_server(lambda: None, path)
        with self.assertRaisesRegex(OSError,
                                    'Address.*is already in use'):
            self.loop.run_until_complete(coro)

    def test_create_unix_server_ssl_bool(self):
        coro = self.loop.create_unix_server(lambda: None, path='spam',
                                            ssl=True)
        with self.assertRaisesRegex(TypeError,
                                    'ssl argument must be an SSLContext'):
            self.loop.run_until_complete(coro)

    def test_create_unix_server_nopath_nosock(self):
        coro = self.loop.create_unix_server(lambda: None, path=None)
        with self.assertRaisesRegex(ValueError,
                                    'path was not specified, and no sock'):
            self.loop.run_until_complete(coro)

    def test_create_unix_server_path_inetsock(self):
        sock = socket.socket()
        with sock:
            coro = self.loop.create_unix_server(lambda: None, path=None,
                                                sock=sock)
            with self.assertRaisesRegex(ValueError,
                                        'A UNIX Domain Stream.*was expected'):
                self.loop.run_until_complete(coro)

    def test_create_unix_server_path_dgram(self):
        sock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
        with sock:
            coro = self.loop.create_unix_server(lambda: None, path=None,
                                                sock=sock)
            with self.assertRaisesRegex(ValueError,
                                        'A UNIX Domain Stream.*was expected'):
                self.loop.run_until_complete(coro)

    @unittest.skipUnless(hasattr(socket, 'SOCK_NONBLOCK'),
                         'no socket.SOCK_NONBLOCK (linux only)')
    @socket_helper.skip_unless_bind_unix_socket
    def test_create_unix_server_path_stream_bittype(self):
        fn = test_utils.gen_unix_socket_path()
        self.addCleanup(os_helper.unlink, fn)

        sock = socket.socket(socket.AF_UNIX,
                             socket.SOCK_STREAM | socket.SOCK_NONBLOCK)
        with sock:
            sock.bind(fn)
            coro = self.loop.create_unix_server(lambda: None, path=None,
                                                sock=sock)
            srv = self.loop.run_until_complete(coro)
            srv.close()
            self.loop.run_until_complete(srv.wait_closed())

    def test_create_unix_server_ssl_timeout_with_plain_sock(self):
        coro = self.loop.create_unix_server(lambda: None, path='spam',
                                            ssl_handshake_timeout=1)
        with self.assertRaisesRegex(
                ValueError,
                'ssl_handshake_timeout is only meaningful with ssl'):
            self.loop.run_until_complete(coro)

    def test_create_unix_connection_path_inetsock(self):
        sock = socket.socket()
        with sock:
            coro = self.loop.create_unix_connection(lambda: None,
                                                    sock=sock)
            with self.assertRaisesRegex(ValueError,
                                        'A UNIX Domain Stream.*was expected'):
                self.loop.run_until_complete(coro)

    @mock.patch('asyncio.unix_events.socket')
    def test_create_unix_server_bind_error(self, m_socket):
        # Ensure that the socket is closed on any bind error
        sock = mock.Mock()
        m_socket.socket.return_value = sock

        sock.bind.side_effect = OSError
        coro = self.loop.create_unix_server(lambda: None, path="/test")
        with self.assertRaises(OSError):
            self.loop.run_until_complete(coro)
        self.assertTrue(sock.close.called)

        sock.bind.side_effect = MemoryError
        coro = self.loop.create_unix_server(lambda: None, path="/test")
        with self.assertRaises(MemoryError):
            self.loop.run_until_complete(coro)
        self.assertTrue(sock.close.called)

    def test_create_unix_connection_path_sock(self):
        coro = self.loop.create_unix_connection(
            lambda: None, os.devnull, sock=object())
        with self.assertRaisesRegex(ValueError, 'path and sock can not be'):
            self.loop.run_until_complete(coro)

    def test_create_unix_connection_nopath_nosock(self):
        coro = self.loop.create_unix_connection(
            lambda: None, None)
        with self.assertRaisesRegex(ValueError,
                                    'no path and sock were specified'):
            self.loop.run_until_complete(coro)

    def test_create_unix_connection_nossl_serverhost(self):
        coro = self.loop.create_unix_connection(
            lambda: None, os.devnull, server_hostname='spam')
        with self.assertRaisesRegex(ValueError,
                                    'server_hostname is only meaningful'):
            self.loop.run_until_complete(coro)

    def test_create_unix_connection_ssl_noserverhost(self):
        coro = self.loop.create_unix_connection(
            lambda: None, os.devnull, ssl=True)

        with self.assertRaisesRegex(
            ValueError, 'you have to pass server_hostname when using ssl'):

            self.loop.run_until_complete(coro)

    def test_create_unix_connection_ssl_timeout_with_plain_sock(self):
        coro = self.loop.create_unix_connection(lambda: None, path='spam',
                                            ssl_handshake_timeout=1)
        with self.assertRaisesRegex(
                ValueError,
                'ssl_handshake_timeout is only meaningful with ssl'):
            self.loop.run_until_complete(coro)


@unittest.skipUnless(hasattr(os, 'sendfile'),
                     'sendfile is not supported')
class SelectorEventLoopUnixSockSendfileTests(test_utils.TestCase):
    DATA = b"12345abcde" * 16 * 1024  # 160 KiB

    class MyProto(asyncio.Protocol):

        def __init__(self, loop):
            self.started = False
            self.closed = False
            self.data = bytearray()
            self.fut = loop.create_future()
            self.transport = None
            self._ready = loop.create_future()

        def connection_made(self, transport):
            self.started = True
            self.transport = transport
            self._ready.set_result(None)

        def data_received(self, data):
            self.data.extend(data)

        def connection_lost(self, exc):
            self.closed = True
            self.fut.set_result(None)

        async def wait_closed(self):
            await self.fut

    @classmethod
    def setUpClass(cls):
        with open(os_helper.TESTFN, 'wb') as fp:
            fp.write(cls.DATA)
        super().setUpClass()

    @classmethod
    def tearDownClass(cls):
        os_helper.unlink(os_helper.TESTFN)
        super().tearDownClass()

    def setUp(self):
        self.loop = asyncio.new_event_loop()
        self.set_event_loop(self.loop)
        self.file = open(os_helper.TESTFN, 'rb')
        self.addCleanup(self.file.close)
        super().setUp()

    def make_socket(self, cleanup=True):
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.setblocking(False)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, 1024)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, 1024)
        if cleanup:
            self.addCleanup(sock.close)
        return sock

    def run_loop(self, coro):
        return self.loop.run_until_complete(coro)

    def prepare(self):
        sock = self.make_socket()
        proto = self.MyProto(self.loop)
        port = socket_helper.find_unused_port()
        srv_sock = self.make_socket(cleanup=False)
        srv_sock.bind((socket_helper.HOST, port))
        server = self.run_loop(self.loop.create_server(
            lambda: proto, sock=srv_sock))
        self.run_loop(self.loop.sock_connect(sock, (socket_helper.HOST, port)))
        self.run_loop(proto._ready)

        def cleanup():
            proto.transport.close()
            self.run_loop(proto.wait_closed())

            server.close()
            self.run_loop(server.wait_closed())

        self.addCleanup(cleanup)

        return sock, proto

    def test_sock_sendfile_not_available(self):
        sock, proto = self.prepare()
        with mock.patch('asyncio.unix_events.os', spec=[]):
            with self.assertRaisesRegex(asyncio.SendfileNotAvailableError,
                                        "os[.]sendfile[(][)] is not available"):
                self.run_loop(self.loop._sock_sendfile_native(sock, self.file,
                                                              0, None))
        self.assertEqual(self.file.tell(), 0)

    def test_sock_sendfile_not_a_file(self):
        sock, proto = self.prepare()
        f = object()
        with self.assertRaisesRegex(asyncio.SendfileNotAvailableError,
                                    "not a regular file"):
            self.run_loop(self.loop._sock_sendfile_native(sock, f,
                                                          0, None))
        self.assertEqual(self.file.tell(), 0)

    def test_sock_sendfile_iobuffer(self):
        sock, proto = self.prepare()
        f = io.BytesIO()
        with self.assertRaisesRegex(asyncio.SendfileNotAvailableError,
                                    "not a regular file"):
            self.run_loop(self.loop._sock_sendfile_native(sock, f,
                                                          0, None))
        self.assertEqual(self.file.tell(), 0)

    def test_sock_sendfile_not_regular_file(self):
        sock, proto = self.prepare()
        f = mock.Mock()
        f.fileno.return_value = -1
        with self.assertRaisesRegex(asyncio.SendfileNotAvailableError,
                                    "not a regular file"):
            self.run_loop(self.loop._sock_sendfile_native(sock, f,
                                                          0, None))
        self.assertEqual(self.file.tell(), 0)

    def test_sock_sendfile_cancel1(self):
        sock, proto = self.prepare()

        fut = self.loop.create_future()
        fileno = self.file.fileno()
        self.loop._sock_sendfile_native_impl(fut, None, sock, fileno,
                                             0, None, len(self.DATA), 0)
        fut.cancel()
        with contextlib.suppress(asyncio.CancelledError):
            self.run_loop(fut)
        with self.assertRaises(KeyError):
            self.loop._selector.get_key(sock)

    def test_sock_sendfile_cancel2(self):
        sock, proto = self.prepare()

        fut = self.loop.create_future()
        fileno = self.file.fileno()
        self.loop._sock_sendfile_native_impl(fut, None, sock, fileno,
                                             0, None, len(self.DATA), 0)
        fut.cancel()
        self.loop._sock_sendfile_native_impl(fut, sock.fileno(), sock, fileno,
                                             0, None, len(self.DATA), 0)
        with self.assertRaises(KeyError):
            self.loop._selector.get_key(sock)

    def test_sock_sendfile_blocking_error(self):
        sock, proto = self.prepare()

        fileno = self.file.fileno()
        fut = mock.Mock()
        fut.cancelled.return_value = False
        with mock.patch('os.sendfile', side_effect=BlockingIOError()):
            self.loop._sock_sendfile_native_impl(fut, None, sock, fileno,
                                                 0, None, len(self.DATA), 0)
        key = self.loop._selector.get_key(sock)
        self.assertIsNotNone(key)
        fut.add_done_callback.assert_called_once_with(mock.ANY)

    def test_sock_sendfile_os_error_first_call(self):
        sock, proto = self.prepare()

        fileno = self.file.fileno()
        fut = self.loop.create_future()
        with mock.patch('os.sendfile', side_effect=OSError()):
            self.loop._sock_sendfile_native_impl(fut, None, sock, fileno,
                                                 0, None, len(self.DATA), 0)
        with self.assertRaises(KeyError):
            self.loop._selector.get_key(sock)
        exc = fut.exception()
        self.assertIsInstance(exc, asyncio.SendfileNotAvailableError)
        self.assertEqual(0, self.file.tell())

    def test_sock_sendfile_os_error_next_call(self):
        sock, proto = self.prepare()

        fileno = self.file.fileno()
        fut = self.loop.create_future()
        err = OSError()
        with mock.patch('os.sendfile', side_effect=err):
            self.loop._sock_sendfile_native_impl(fut, sock.fileno(),
                                                 sock, fileno,
                                                 1000, None, len(self.DATA),
                                                 1000)
        with self.assertRaises(KeyError):
            self.loop._selector.get_key(sock)
        exc = fut.exception()
        self.assertIs(exc, err)
        self.assertEqual(1000, self.file.tell())

    def test_sock_sendfile_exception(self):
        sock, proto = self.prepare()

        fileno = self.file.fileno()
        fut = self.loop.create_future()
        err = asyncio.SendfileNotAvailableError()
        with mock.patch('os.sendfile', side_effect=err):
            self.loop._sock_sendfile_native_impl(fut, sock.fileno(),
                                                 sock, fileno,
                                                 1000, None, len(self.DATA),
                                                 1000)
        with self.assertRaises(KeyError):
            self.loop._selector.get_key(sock)
        exc = fut.exception()
        self.assertIs(exc, err)
        self.assertEqual(1000, self.file.tell())


class UnixReadPipeTransportTests(test_utils.TestCase):

    def setUp(self):
        super().setUp()
        self.loop = self.new_test_loop()
        self.protocol = test_utils.make_test_protocol(asyncio.Protocol)
        self.pipe = mock.Mock(spec_set=io.RawIOBase)
        self.pipe.fileno.return_value = 5

        blocking_patcher = mock.patch('os.set_blocking')
        blocking_patcher.start()
        self.addCleanup(blocking_patcher.stop)

        fstat_patcher = mock.patch('os.fstat')
        m_fstat = fstat_patcher.start()
        st = mock.Mock()
        st.st_mode = stat.S_IFIFO
        m_fstat.return_value = st
        self.addCleanup(fstat_patcher.stop)

    def read_pipe_transport(self, waiter=None):
        transport = unix_events._UnixReadPipeTransport(self.loop, self.pipe,
                                                       self.protocol,
                                                       waiter=waiter)
        self.addCleanup(close_pipe_transport, transport)
        return transport

    def test_ctor(self):
        waiter = self.loop.create_future()
        tr = self.read_pipe_transport(waiter=waiter)
        self.loop.run_until_complete(waiter)

        self.protocol.connection_made.assert_called_with(tr)
        self.loop.assert_reader(5, tr._read_ready)
        self.assertIsNone(waiter.result())

    @mock.patch('os.read')
    def test__read_ready(self, m_read):
        tr = self.read_pipe_transport()
        m_read.return_value = b'data'
        tr._read_ready()

        m_read.assert_called_with(5, tr.max_size)
        self.protocol.data_received.assert_called_with(b'data')

    @mock.patch('os.read')
    def test__read_ready_eof(self, m_read):
        tr = self.read_pipe_transport()
        m_read.return_value = b''
        tr._read_ready()

        m_read.assert_called_with(5, tr.max_size)
        self.assertFalse(self.loop.readers)
        test_utils.run_briefly(self.loop)
        self.protocol.eof_received.assert_called_with()
        self.protocol.connection_lost.assert_called_with(None)

    @mock.patch('os.read')
    def test__read_ready_blocked(self, m_read):
        tr = self.read_pipe_transport()
        m_read.side_effect = BlockingIOError
        tr._read_ready()

        m_read.assert_called_with(5, tr.max_size)
        test_utils.run_briefly(self.loop)
        self.assertFalse(self.protocol.data_received.called)

    @mock.patch('asyncio.log.logger.error')
    @mock.patch('os.read')
    def test__read_ready_error(self, m_read, m_logexc):
        tr = self.read_pipe_transport()
        err = OSError()
        m_read.side_effect = err
        tr._close = mock.Mock()
        tr._read_ready()

        m_read.assert_called_with(5, tr.max_size)
        tr._close.assert_called_with(err)
        m_logexc.assert_called_with(
            test_utils.MockPattern(
                'Fatal read error on pipe transport'
                '\nprotocol:.*\ntransport:.*'),
            exc_info=(OSError, MOCK_ANY, MOCK_ANY))

    @mock.patch('os.read')
    def test_pause_reading(self, m_read):
        tr = self.read_pipe_transport()
        m = mock.Mock()
        self.loop.add_reader(5, m)
        tr.pause_reading()
        self.assertFalse(self.loop.readers)

    @mock.patch('os.read')
    def test_resume_reading(self, m_read):
        tr = self.read_pipe_transport()
        tr.pause_reading()
        tr.resume_reading()
        self.loop.assert_reader(5, tr._read_ready)

    @mock.patch('os.read')
    def test_close(self, m_read):
        tr = self.read_pipe_transport()
        tr._close = mock.Mock()
        tr.close()
        tr._close.assert_called_with(None)

    @mock.patch('os.read')
    def test_close_already_closing(self, m_read):
        tr = self.read_pipe_transport()
        tr._closing = True
        tr._close = mock.Mock()
        tr.close()
        self.assertFalse(tr._close.called)

    @mock.patch('os.read')
    def test__close(self, m_read):
        tr = self.read_pipe_transport()
        err = object()
        tr._close(err)
        self.assertTrue(tr.is_closing())
        self.assertFalse(self.loop.readers)
        test_utils.run_briefly(self.loop)
        self.protocol.connection_lost.assert_called_with(err)

    def test__call_connection_lost(self):
        tr = self.read_pipe_transport()
        self.assertIsNotNone(tr._protocol)
        self.assertIsNotNone(tr._loop)

        err = None
        tr._call_connection_lost(err)
        self.protocol.connection_lost.assert_called_with(err)
        self.pipe.close.assert_called_with()

        self.assertIsNone(tr._protocol)
        self.assertIsNone(tr._loop)

    def test__call_connection_lost_with_err(self):
        tr = self.read_pipe_transport()
        self.assertIsNotNone(tr._protocol)
        self.assertIsNotNone(tr._loop)

        err = OSError()
        tr._call_connection_lost(err)
        self.protocol.connection_lost.assert_called_with(err)
        self.pipe.close.assert_called_with()

        self.assertIsNone(tr._protocol)
        self.assertIsNone(tr._loop)

    def test_pause_reading_on_closed_pipe(self):
        tr = self.read_pipe_transport()
        tr.close()
        test_utils.run_briefly(self.loop)
        self.assertIsNone(tr._loop)
        tr.pause_reading()

    def test_pause_reading_on_paused_pipe(self):
        tr = self.read_pipe_transport()
        tr.pause_reading()
        # the second call should do nothing
        tr.pause_reading()

    def test_resume_reading_on_closed_pipe(self):
        tr = self.read_pipe_transport()
        tr.close()
        test_utils.run_briefly(self.loop)
        self.assertIsNone(tr._loop)
        tr.resume_reading()

    def test_resume_reading_on_paused_pipe(self):
        tr = self.read_pipe_transport()
        # the pipe is not paused
        # resuming should do nothing
        tr.resume_reading()


class UnixWritePipeTransportTests(test_utils.TestCase):

    def setUp(self):
        super().setUp()
        self.loop = self.new_test_loop()
        self.protocol = test_utils.make_test_protocol(asyncio.BaseProtocol)
        self.pipe = mock.Mock(spec_set=io.RawIOBase)
        self.pipe.fileno.return_value = 5

        blocking_patcher = mock.patch('os.set_blocking')
        blocking_patcher.start()
        self.addCleanup(blocking_patcher.stop)

        fstat_patcher = mock.patch('os.fstat')
        m_fstat = fstat_patcher.start()
        st = mock.Mock()
        st.st_mode = stat.S_IFSOCK
        m_fstat.return_value = st
        self.addCleanup(fstat_patcher.stop)

    def write_pipe_transport(self, waiter=None):
        transport = unix_events._UnixWritePipeTransport(self.loop, self.pipe,
                                                        self.protocol,
                                                        waiter=waiter)
        self.addCleanup(close_pipe_transport, transport)
        return transport

    def test_ctor(self):
        waiter = self.loop.create_future()
        tr = self.write_pipe_transport(waiter=waiter)
        self.loop.run_until_complete(waiter)

        self.protocol.connection_made.assert_called_with(tr)
        self.loop.assert_reader(5, tr._read_ready)
        self.assertEqual(None, waiter.result())

    def test_can_write_eof(self):
        tr = self.write_pipe_transport()
        self.assertTrue(tr.can_write_eof())

    @mock.patch('os.write')
    def test_write(self, m_write):
        tr = self.write_pipe_transport()
        m_write.return_value = 4
        tr.write(b'data')
        m_write.assert_called_with(5, b'data')
        self.assertFalse(self.loop.writers)
        self.assertEqual(bytearray(), tr._buffer)

    @mock.patch('os.write')
    def test_write_no_data(self, m_write):
        tr = self.write_pipe_transport()
        tr.write(b'')
        self.assertFalse(m_write.called)
        self.assertFalse(self.loop.writers)
        self.assertEqual(bytearray(b''), tr._buffer)

    @mock.patch('os.write')
    def test_write_partial(self, m_write):
        tr = self.write_pipe_transport()
        m_write.return_value = 2
        tr.write(b'data')
        self.loop.assert_writer(5, tr._write_ready)
        self.assertEqual(bytearray(b'ta'), tr._buffer)

    @mock.patch('os.write')
    def test_write_buffer(self, m_write):
        tr = self.write_pipe_transport()
        self.loop.add_writer(5, tr._write_ready)
        tr._buffer = bytearray(b'previous')
        tr.write(b'data')
        self.assertFalse(m_write.called)
        self.loop.assert_writer(5, tr._write_ready)
        self.assertEqual(bytearray(b'previousdata'), tr._buffer)

    @mock.patch('os.write')
    def test_write_again(self, m_write):
        tr = self.write_pipe_transport()
        m_write.side_effect = BlockingIOError()
        tr.write(b'data')
        m_write.assert_called_with(5, bytearray(b'data'))
        self.loop.assert_writer(5, tr._write_ready)
        self.assertEqual(bytearray(b'data'), tr._buffer)

    @mock.patch('asyncio.unix_events.logger')
    @mock.patch('os.write')
    def test_write_err(self, m_write, m_log):
        tr = self.write_pipe_transport()
        err = OSError()
        m_write.side_effect = err
        tr._fatal_error = mock.Mock()
        tr.write(b'data')
        m_write.assert_called_with(5, b'data')
        self.assertFalse(self.loop.writers)
        self.assertEqual(bytearray(), tr._buffer)
        tr._fatal_error.assert_called_with(
                            err,
                            'Fatal write error on pipe transport')
        self.assertEqual(1, tr._conn_lost)

        tr.write(b'data')
        self.assertEqual(2, tr._conn_lost)
        tr.write(b'data')
        tr.write(b'data')
        tr.write(b'data')
        tr.write(b'data')
        # This is a bit overspecified. :-(
        m_log.warning.assert_called_with(
            'pipe closed by peer or os.write(pipe, data) raised exception.')
        tr.close()

    @mock.patch('os.write')
    def test_write_close(self, m_write):
        tr = self.write_pipe_transport()
        tr._read_ready()  # pipe was closed by peer

        tr.write(b'data')
        self.assertEqual(tr._conn_lost, 1)
        tr.write(b'data')
        self.assertEqual(tr._conn_lost, 2)

    def test__read_ready(self):
        tr = self.write_pipe_transport()
        tr._read_ready()
        self.assertFalse(self.loop.readers)
        self.assertFalse(self.loop.writers)
        self.assertTrue(tr.is_closing())
        test_utils.run_briefly(self.loop)
        self.protocol.connection_lost.assert_called_with(None)

    @mock.patch('os.write')
    def test__write_ready(self, m_write):
        tr = self.write_pipe_transport()
        self.loop.add_writer(5, tr._write_ready)
        tr._buffer = bytearray(b'data')
        m_write.return_value = 4
        tr._write_ready()
        self.assertFalse(self.loop.writers)
        self.assertEqual(bytearray(), tr._buffer)

    @mock.patch('os.write')
    def test__write_ready_partial(self, m_write):
        tr = self.write_pipe_transport()
        self.loop.add_writer(5, tr._write_ready)
        tr._buffer = bytearray(b'data')
        m_write.return_value = 3
        tr._write_ready()
        self.loop.assert_writer(5, tr._write_ready)
        self.assertEqual(bytearray(b'a'), tr._buffer)

    @mock.patch('os.write')
    def test__write_ready_again(self, m_write):
        tr = self.write_pipe_transport()
        self.loop.add_writer(5, tr._write_ready)
        tr._buffer = bytearray(b'data')
        m_write.side_effect = BlockingIOError()
        tr._write_ready()
        m_write.assert_called_with(5, bytearray(b'data'))
        self.loop.assert_writer(5, tr._write_ready)
        self.assertEqual(bytearray(b'data'), tr._buffer)

    @mock.patch('os.write')
    def test__write_ready_empty(self, m_write):
        tr = self.write_pipe_transport()
        self.loop.add_writer(5, tr._write_ready)
        tr._buffer = bytearray(b'data')
        m_write.return_value = 0
        tr._write_ready()
        m_write.assert_called_with(5, bytearray(b'data'))
        self.loop.assert_writer(5, tr._write_ready)
        self.assertEqual(bytearray(b'data'), tr._buffer)

    @mock.patch('asyncio.log.logger.error')
    @mock.patch('os.write')
    def test__write_ready_err(self, m_write, m_logexc):
        tr = self.write_pipe_transport()
        self.loop.add_writer(5, tr._write_ready)
        tr._buffer = bytearray(b'data')
        m_write.side_effect = err = OSError()
        tr._write_ready()
        self.assertFalse(self.loop.writers)
        self.assertFalse(self.loop.readers)
        self.assertEqual(bytearray(), tr._buffer)
        self.assertTrue(tr.is_closing())
        m_logexc.assert_not_called()
        self.assertEqual(1, tr._conn_lost)
        test_utils.run_briefly(self.loop)
        self.protocol.connection_lost.assert_called_with(err)

    @mock.patch('os.write')
    def test__write_ready_closing(self, m_write):
        tr = self.write_pipe_transport()
        self.loop.add_writer(5, tr._write_ready)
        tr._closing = True
        tr._buffer = bytearray(b'data')
        m_write.return_value = 4
        tr._write_ready()
        self.assertFalse(self.loop.writers)
        self.assertFalse(self.loop.readers)
        self.assertEqual(bytearray(), tr._buffer)
        self.protocol.connection_lost.assert_called_with(None)
        self.pipe.close.assert_called_with()

    @mock.patch('os.write')
    def test_abort(self, m_write):
        tr = self.write_pipe_transport()
        self.loop.add_writer(5, tr._write_ready)
        self.loop.add_reader(5, tr._read_ready)
        tr._buffer = [b'da', b'ta']
        tr.abort()
        self.assertFalse(m_write.called)
        self.assertFalse(self.loop.readers)
        self.assertFalse(self.loop.writers)
        self.assertEqual([], tr._buffer)
        self.assertTrue(tr.is_closing())
        test_utils.run_briefly(self.loop)
        self.protocol.connection_lost.assert_called_with(None)

    def test__call_connection_lost(self):
        tr = self.write_pipe_transport()
        self.assertIsNotNone(tr._protocol)
        self.assertIsNotNone(tr._loop)

        err = None
        tr._call_connection_lost(err)
        self.protocol.connection_lost.assert_called_with(err)
        self.pipe.close.assert_called_with()

        self.assertIsNone(tr._protocol)
        self.assertIsNone(tr._loop)

    def test__call_connection_lost_with_err(self):
        tr = self.write_pipe_transport()
        self.assertIsNotNone(tr._protocol)
        self.assertIsNotNone(tr._loop)

        err = OSError()
        tr._call_connection_lost(err)
        self.protocol.connection_lost.assert_called_with(err)
        self.pipe.close.assert_called_with()

        self.assertIsNone(tr._protocol)
        self.assertIsNone(tr._loop)

    def test_close(self):
        tr = self.write_pipe_transport()
        tr.write_eof = mock.Mock()
        tr.close()
        tr.write_eof.assert_called_with()

        # closing the transport twice must not fail
        tr.close()

    def test_close_closing(self):
        tr = self.write_pipe_transport()
        tr.write_eof = mock.Mock()
        tr._closing = True
        tr.close()
        self.assertFalse(tr.write_eof.called)

    def test_write_eof(self):
        tr = self.write_pipe_transport()
        tr.write_eof()
        self.assertTrue(tr.is_closing())
        self.assertFalse(self.loop.readers)
        test_utils.run_briefly(self.loop)
        self.protocol.connection_lost.assert_called_with(None)

    def test_write_eof_pending(self):
        tr = self.write_pipe_transport()
        tr._buffer = [b'data']
        tr.write_eof()
        self.assertTrue(tr.is_closing())
        self.assertFalse(self.protocol.connection_lost.called)


class AbstractChildWatcherTests(unittest.TestCase):

    def test_warns_on_subclassing(self):
        with self.assertWarns(DeprecationWarning):
            class MyWatcher(asyncio.AbstractChildWatcher):
                pass

    def test_not_implemented(self):
        f = mock.Mock()
        watcher = asyncio.AbstractChildWatcher()
        self.assertRaises(
            NotImplementedError, watcher.add_child_handler, f, f)
        self.assertRaises(
            NotImplementedError, watcher.remove_child_handler, f)
        self.assertRaises(
            NotImplementedError, watcher.attach_loop, f)
        self.assertRaises(
            NotImplementedError, watcher.close)
        self.assertRaises(
            NotImplementedError, watcher.is_active)
        self.assertRaises(
            NotImplementedError, watcher.__enter__)
        self.assertRaises(
            NotImplementedError, watcher.__exit__, f, f, f)


class BaseChildWatcherTests(unittest.TestCase):

    def test_not_implemented(self):
        f = mock.Mock()
        watcher = unix_events.BaseChildWatcher()
        self.assertRaises(
            NotImplementedError, watcher._do_waitpid, f)


class ChildWatcherTestsMixin:

    ignore_warnings = mock.patch.object(log.logger, "warning")

    def setUp(self):
        super().setUp()
        self.loop = self.new_test_loop()
        self.running = False
        self.zombies = {}

        with mock.patch.object(
                self.loop, "add_signal_handler") as self.m_add_signal_handler:
            self.watcher = self.create_watcher()
            self.watcher.attach_loop(self.loop)

    def waitpid(self, pid, flags):
        if isinstance(self.watcher, asyncio.SafeChildWatcher) or pid != -1:
            self.assertGreater(pid, 0)
        try:
            if pid < 0:
                return self.zombies.popitem()
            else:
                return pid, self.zombies.pop(pid)
        except KeyError:
            pass
        if self.running:
            return 0, 0
        else:
            raise ChildProcessError()

    def add_zombie(self, pid, status):
        self.zombies[pid] = status

    def waitstatus_to_exitcode(self, status):
        if status > 32768:
            return status - 32768
        elif 32700 < status < 32768:
            return status - 32768
        else:
            return status

    def test_create_watcher(self):
        self.m_add_signal_handler.assert_called_once_with(
            signal.SIGCHLD, self.watcher._sig_chld)

    def waitpid_mocks(func):
        def wrapped_func(self):
            def patch(target, wrapper):
                return mock.patch(target, wraps=wrapper,
                                  new_callable=mock.Mock)

            with patch('asyncio.unix_events.waitstatus_to_exitcode', self.waitstatus_to_exitcode), \
                 patch('os.waitpid', self.waitpid) as m_waitpid:
                func(self, m_waitpid)
        return wrapped_func

    @waitpid_mocks
    def test_sigchld(self, m_waitpid):
        # register a child
        callback = mock.Mock()

        with self.watcher:
            self.running = True
            self.watcher.add_child_handler(42, callback, 9, 10, 14)

        self.assertFalse(callback.called)

        # child is running
        self.watcher._sig_chld()

        self.assertFalse(callback.called)

        # child terminates (returncode 12)
        self.running = False
        self.add_zombie(42, EXITCODE(12))
        self.watcher._sig_chld()

        callback.assert_called_once_with(42, 12, 9, 10, 14)

        callback.reset_mock()

        # ensure that the child is effectively reaped
        self.add_zombie(42, EXITCODE(13))
        with self.ignore_warnings:
            self.watcher._sig_chld()

        self.assertFalse(callback.called)

        # sigchld called again
        self.zombies.clear()
        self.watcher._sig_chld()

        self.assertFalse(callback.called)

    @waitpid_mocks
    def test_sigchld_two_children(self, m_waitpid):
        callback1 = mock.Mock()
        callback2 = mock.Mock()

        # register child 1
        with self.watcher:
            self.running = True
            self.watcher.add_child_handler(43, callback1, 7, 8)

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

        # register child 2
        with self.watcher:
            self.watcher.add_child_handler(44, callback2, 147, 18)

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

        # children are running
        self.watcher._sig_chld()

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

        # child 1 terminates (signal 3)
        self.add_zombie(43, SIGNAL(3))
        self.watcher._sig_chld()

        callback1.assert_called_once_with(43, -3, 7, 8)
        self.assertFalse(callback2.called)

        callback1.reset_mock()

        # child 2 still running
        self.watcher._sig_chld()

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

        # child 2 terminates (code 108)
        self.add_zombie(44, EXITCODE(108))
        self.running = False
        self.watcher._sig_chld()

        callback2.assert_called_once_with(44, 108, 147, 18)
        self.assertFalse(callback1.called)

        callback2.reset_mock()

        # ensure that the children are effectively reaped
        self.add_zombie(43, EXITCODE(14))
        self.add_zombie(44, EXITCODE(15))
        with self.ignore_warnings:
            self.watcher._sig_chld()

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

        # sigchld called again
        self.zombies.clear()
        self.watcher._sig_chld()

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

    @waitpid_mocks
    def test_sigchld_two_children_terminating_together(self, m_waitpid):
        callback1 = mock.Mock()
        callback2 = mock.Mock()

        # register child 1
        with self.watcher:
            self.running = True
            self.watcher.add_child_handler(45, callback1, 17, 8)

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

        # register child 2
        with self.watcher:
            self.watcher.add_child_handler(46, callback2, 1147, 18)

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

        # children are running
        self.watcher._sig_chld()

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

        # child 1 terminates (code 78)
        # child 2 terminates (signal 5)
        self.add_zombie(45, EXITCODE(78))
        self.add_zombie(46, SIGNAL(5))
        self.running = False
        self.watcher._sig_chld()

        callback1.assert_called_once_with(45, 78, 17, 8)
        callback2.assert_called_once_with(46, -5, 1147, 18)

        callback1.reset_mock()
        callback2.reset_mock()

        # ensure that the children are effectively reaped
        self.add_zombie(45, EXITCODE(14))
        self.add_zombie(46, EXITCODE(15))
        with self.ignore_warnings:
            self.watcher._sig_chld()

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

    @waitpid_mocks
    def test_sigchld_race_condition(self, m_waitpid):
        # register a child
        callback = mock.Mock()

        with self.watcher:
            # child terminates before being registered
            self.add_zombie(50, EXITCODE(4))
            self.watcher._sig_chld()

            self.watcher.add_child_handler(50, callback, 1, 12)

        callback.assert_called_once_with(50, 4, 1, 12)
        callback.reset_mock()

        # ensure that the child is effectively reaped
        self.add_zombie(50, SIGNAL(1))
        with self.ignore_warnings:
            self.watcher._sig_chld()

        self.assertFalse(callback.called)

    @waitpid_mocks
    def test_sigchld_replace_handler(self, m_waitpid):
        callback1 = mock.Mock()
        callback2 = mock.Mock()

        # register a child
        with self.watcher:
            self.running = True
            self.watcher.add_child_handler(51, callback1, 19)

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

        # register the same child again
        with self.watcher:
            self.watcher.add_child_handler(51, callback2, 21)

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

        # child terminates (signal 8)
        self.running = False
        self.add_zombie(51, SIGNAL(8))
        self.watcher._sig_chld()

        callback2.assert_called_once_with(51, -8, 21)
        self.assertFalse(callback1.called)

        callback2.reset_mock()

        # ensure that the child is effectively reaped
        self.add_zombie(51, EXITCODE(13))
        with self.ignore_warnings:
            self.watcher._sig_chld()

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)

    @waitpid_mocks
    def test_sigchld_remove_handler(self, m_waitpid):
        callback = mock.Mock()

        # register a child
        with self.watcher:
            self.running = True
            self.watcher.add_child_handler(52, callback, 1984)

        self.assertFalse(callback.called)

        # unregister the child
        self.watcher.remove_child_handler(52)

        self.assertFalse(callback.called)

        # child terminates (code 99)
        self.running = False
        self.add_zombie(52, EXITCODE(99))
        with self.ignore_warnings:
            self.watcher._sig_chld()

        self.assertFalse(callback.called)

    @waitpid_mocks
    def test_sigchld_unknown_status(self, m_waitpid):
        callback = mock.Mock()

        # register a child
        with self.watcher:
            self.running = True
            self.watcher.add_child_handler(53, callback, -19)

        self.assertFalse(callback.called)

        # terminate with unknown status
        self.zombies[53] = 1178
        self.running = False
        self.watcher._sig_chld()

        callback.assert_called_once_with(53, 1178, -19)

        callback.reset_mock()

        # ensure that the child is effectively reaped
        self.add_zombie(53, EXITCODE(101))
        with self.ignore_warnings:
            self.watcher._sig_chld()

        self.assertFalse(callback.called)

    @waitpid_mocks
    def test_remove_child_handler(self, m_waitpid):
        callback1 = mock.Mock()
        callback2 = mock.Mock()
        callback3 = mock.Mock()

        # register children
        with self.watcher:
            self.running = True
            self.watcher.add_child_handler(54, callback1, 1)
            self.watcher.add_child_handler(55, callback2, 2)
            self.watcher.add_child_handler(56, callback3, 3)

        # remove child handler 1
        self.assertTrue(self.watcher.remove_child_handler(54))

        # remove child handler 2 multiple times
        self.assertTrue(self.watcher.remove_child_handler(55))
        self.assertFalse(self.watcher.remove_child_handler(55))
        self.assertFalse(self.watcher.remove_child_handler(55))

        # all children terminate
        self.add_zombie(54, EXITCODE(0))
        self.add_zombie(55, EXITCODE(1))
        self.add_zombie(56, EXITCODE(2))
        self.running = False
        with self.ignore_warnings:
            self.watcher._sig_chld()

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)
        callback3.assert_called_once_with(56, 2, 3)

    @waitpid_mocks
    def test_sigchld_unhandled_exception(self, m_waitpid):
        callback = mock.Mock()

        # register a child
        with self.watcher:
            self.running = True
            self.watcher.add_child_handler(57, callback)

        # raise an exception
        m_waitpid.side_effect = ValueError

        with mock.patch.object(log.logger,
                               'error') as m_error:

            self.assertEqual(self.watcher._sig_chld(), None)
            self.assertTrue(m_error.called)

    @waitpid_mocks
    def test_sigchld_child_reaped_elsewhere(self, m_waitpid):
        # register a child
        callback = mock.Mock()

        with self.watcher:
            self.running = True
            self.watcher.add_child_handler(58, callback)

        self.assertFalse(callback.called)

        # child terminates
        self.running = False
        self.add_zombie(58, EXITCODE(4))

        # waitpid is called elsewhere
        os.waitpid(58, os.WNOHANG)

        m_waitpid.reset_mock()

        # sigchld
        with self.ignore_warnings:
            self.watcher._sig_chld()

        if isinstance(self.watcher, asyncio.FastChildWatcher):
            # here the FastChildWatcher enters a deadlock
            # (there is no way to prevent it)
            self.assertFalse(callback.called)
        else:
            callback.assert_called_once_with(58, 255)

    @waitpid_mocks
    def test_sigchld_unknown_pid_during_registration(self, m_waitpid):
        # register two children
        callback1 = mock.Mock()
        callback2 = mock.Mock()

        with self.ignore_warnings, self.watcher:
            self.running = True
            # child 1 terminates
            self.add_zombie(591, EXITCODE(7))
            # an unknown child terminates
            self.add_zombie(593, EXITCODE(17))

            self.watcher._sig_chld()

            self.watcher.add_child_handler(591, callback1)
            self.watcher.add_child_handler(592, callback2)

        callback1.assert_called_once_with(591, 7)
        self.assertFalse(callback2.called)

    @waitpid_mocks
    def test_set_loop(self, m_waitpid):
        # register a child
        callback = mock.Mock()

        with self.watcher:
            self.running = True
            self.watcher.add_child_handler(60, callback)

        # attach a new loop
        old_loop = self.loop
        self.loop = self.new_test_loop()
        patch = mock.patch.object

        with patch(old_loop, "remove_signal_handler") as m_old_remove, \
             patch(self.loop, "add_signal_handler") as m_new_add:

            self.watcher.attach_loop(self.loop)

            m_old_remove.assert_called_once_with(
                signal.SIGCHLD)
            m_new_add.assert_called_once_with(
                signal.SIGCHLD, self.watcher._sig_chld)

        # child terminates
        self.running = False
        self.add_zombie(60, EXITCODE(9))
        self.watcher._sig_chld()

        callback.assert_called_once_with(60, 9)

    @waitpid_mocks
    def test_set_loop_race_condition(self, m_waitpid):
        # register 3 children
        callback1 = mock.Mock()
        callback2 = mock.Mock()
        callback3 = mock.Mock()

        with self.watcher:
            self.running = True
            self.watcher.add_child_handler(61, callback1)
            self.watcher.add_child_handler(62, callback2)
            self.watcher.add_child_handler(622, callback3)

        # detach the loop
        old_loop = self.loop
        self.loop = None

        with mock.patch.object(
                old_loop, "remove_signal_handler") as m_remove_signal_handler:

            with self.assertWarnsRegex(
                    RuntimeWarning, 'A loop is being detached'):
                self.watcher.attach_loop(None)

            m_remove_signal_handler.assert_called_once_with(
                signal.SIGCHLD)

        # child 1 & 2 terminate
        self.add_zombie(61, EXITCODE(11))
        self.add_zombie(62, SIGNAL(5))

        # SIGCHLD was not caught
        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)
        self.assertFalse(callback3.called)

        # attach a new loop
        self.loop = self.new_test_loop()

        with mock.patch.object(
                self.loop, "add_signal_handler") as m_add_signal_handler:

            self.watcher.attach_loop(self.loop)

            m_add_signal_handler.assert_called_once_with(
                signal.SIGCHLD, self.watcher._sig_chld)
            callback1.assert_called_once_with(61, 11)  # race condition!
            callback2.assert_called_once_with(62, -5)  # race condition!
            self.assertFalse(callback3.called)

        callback1.reset_mock()
        callback2.reset_mock()

        # child 3 terminates
        self.running = False
        self.add_zombie(622, EXITCODE(19))
        self.watcher._sig_chld()

        self.assertFalse(callback1.called)
        self.assertFalse(callback2.called)
        callback3.assert_called_once_with(622, 19)

    @waitpid_mocks
    def test_close(self, m_waitpid):
        # register two children
        callback1 = mock.Mock()

        with self.watcher:
            self.running = True
            # child 1 terminates
            self.add_zombie(63, EXITCODE(9))
            # other child terminates
            self.add_zombie(65, EXITCODE(18))
            self.watcher._sig_chld()

            self.watcher.add_child_handler(63, callback1)
            self.watcher.add_child_handler(64, callback1)

            self.assertEqual(len(self.watcher._callbacks), 1)
            if isinstance(self.watcher, asyncio.FastChildWatcher):
                self.assertEqual(len(self.watcher._zombies), 1)

            with mock.patch.object(
                    self.loop,
                    "remove_signal_handler") as m_remove_signal_handler:

                self.watcher.close()

                m_remove_signal_handler.assert_called_once_with(
                    signal.SIGCHLD)
                self.assertFalse(self.watcher._callbacks)
                if isinstance(self.watcher, asyncio.FastChildWatcher):
                    self.assertFalse(self.watcher._zombies)


class SafeChildWatcherTests (ChildWatcherTestsMixin, test_utils.TestCase):
    def create_watcher(self):
        with warnings.catch_warnings():
            warnings.simplefilter("ignore", DeprecationWarning)
            return asyncio.SafeChildWatcher()


class FastChildWatcherTests (ChildWatcherTestsMixin, test_utils.TestCase):
    def create_watcher(self):
        with warnings.catch_warnings():
            warnings.simplefilter("ignore", DeprecationWarning)
            return asyncio.FastChildWatcher()


class PolicyTests(unittest.TestCase):

    def create_policy(self):
        return asyncio.DefaultEventLoopPolicy()

    @mock.patch('asyncio.unix_events.can_use_pidfd')
    def test_get_default_child_watcher(self, m_can_use_pidfd):
        m_can_use_pidfd.return_value = False
        policy = self.create_policy()
        self.assertIsNone(policy._watcher)
        with self.assertWarns(DeprecationWarning):
            watcher = policy.get_child_watcher()
        self.assertIsInstance(watcher, asyncio.ThreadedChildWatcher)

        self.assertIs(policy._watcher, watcher)
        with self.assertWarns(DeprecationWarning):
            self.assertIs(watcher, policy.get_child_watcher())

        m_can_use_pidfd.return_value = True
        policy = self.create_policy()
        self.assertIsNone(policy._watcher)
        with self.assertWarns(DeprecationWarning):
            watcher = policy.get_child_watcher()
        self.assertIsInstance(watcher, asyncio.PidfdChildWatcher)

        self.assertIs(policy._watcher, watcher)
        with self.assertWarns(DeprecationWarning):
            self.assertIs(watcher, policy.get_child_watcher())

    def test_get_child_watcher_after_set(self):
        policy = self.create_policy()
        with warnings.catch_warnings():
            warnings.simplefilter("ignore", DeprecationWarning)
            watcher = asyncio.FastChildWatcher()
            policy.set_child_watcher(watcher)

        self.assertIs(policy._watcher, watcher)
        with self.assertWarns(DeprecationWarning):
            self.assertIs(watcher, policy.get_child_watcher())

    def test_get_child_watcher_thread(self):

        def f():
            policy.set_event_loop(policy.new_event_loop())

            self.assertIsInstance(policy.get_event_loop(),
                                  asyncio.AbstractEventLoop)
            with warnings.catch_warnings():
                warnings.simplefilter("ignore", DeprecationWarning)
                watcher = policy.get_child_watcher()

            self.assertIsInstance(watcher, asyncio.SafeChildWatcher)
            self.assertIsNone(watcher._loop)

            policy.get_event_loop().close()

        policy = self.create_policy()
        with warnings.catch_warnings():
            warnings.simplefilter("ignore", DeprecationWarning)
            policy.set_child_watcher(asyncio.SafeChildWatcher())

        th = threading.Thread(target=f)
        th.start()
        th.join()

    def test_child_watcher_replace_mainloop_existing(self):
        policy = self.create_policy()
        loop = policy.new_event_loop()
        policy.set_event_loop(loop)

        # Explicitly setup SafeChildWatcher,
        # default ThreadedChildWatcher has no _loop property
        with warnings.catch_warnings():
            warnings.simplefilter("ignore", DeprecationWarning)
            watcher = asyncio.SafeChildWatcher()
            policy.set_child_watcher(watcher)
        watcher.attach_loop(loop)

        self.assertIs(watcher._loop, loop)

        new_loop = policy.new_event_loop()
        policy.set_event_loop(new_loop)

        self.assertIs(watcher._loop, new_loop)

        policy.set_event_loop(None)

        self.assertIs(watcher._loop, None)

        loop.close()
        new_loop.close()


class TestFunctional(unittest.TestCase):

    def setUp(self):
        self.loop = asyncio.new_event_loop()
        asyncio.set_event_loop(self.loop)

    def tearDown(self):
        self.loop.close()
        asyncio.set_event_loop(None)

    def test_add_reader_invalid_argument(self):
        def assert_raises():
            return self.assertRaisesRegex(ValueError, r'Invalid file object')

        cb = lambda: None

        with assert_raises():
            self.loop.add_reader(object(), cb)
        with assert_raises():
            self.loop.add_writer(object(), cb)

        with assert_raises():
            self.loop.remove_reader(object())
        with assert_raises():
            self.loop.remove_writer(object())

    def test_add_reader_or_writer_transport_fd(self):
        def assert_raises():
            return self.assertRaisesRegex(
                RuntimeError,
                r'File descriptor .* is used by transport')

        async def runner():
            tr, pr = await self.loop.create_connection(
                lambda: asyncio.Protocol(), sock=rsock)

            try:
                cb = lambda: None

                with assert_raises():
                    self.loop.add_reader(rsock, cb)
                with assert_raises():
                    self.loop.add_reader(rsock.fileno(), cb)

                with assert_raises():
                    self.loop.remove_reader(rsock)
                with assert_raises():
                    self.loop.remove_reader(rsock.fileno())

                with assert_raises():
                    self.loop.add_writer(rsock, cb)
                with assert_raises():
                    self.loop.add_writer(rsock.fileno(), cb)

                with assert_raises():
                    self.loop.remove_writer(rsock)
                with assert_raises():
                    self.loop.remove_writer(rsock.fileno())

            finally:
                tr.close()

        rsock, wsock = socket.socketpair()
        try:
            self.loop.run_until_complete(runner())
        finally:
            rsock.close()
            wsock.close()


@support.requires_fork()
class TestFork(unittest.IsolatedAsyncioTestCase):

    async def test_fork_not_share_event_loop(self):
        # The forked process should not share the event loop with the parent
        loop = asyncio.get_running_loop()
        r, w = os.pipe()
        self.addCleanup(os.close, r)
        self.addCleanup(os.close, w)
        pid = os.fork()
        if pid == 0:
            # child
            try:
                with self.assertWarns(DeprecationWarning):
                    loop = asyncio.get_event_loop_policy().get_event_loop()
                os.write(w, b'LOOP:' + str(id(loop)).encode())
            except RuntimeError:
                os.write(w, b'NO LOOP')
            except BaseException as e:
                os.write(w, b'ERROR:' + ascii(e).encode())
            finally:
                os._exit(0)
        else:
            # parent
            result = os.read(r, 100)
            self.assertEqual(result[:5], b'LOOP:', result)
            self.assertNotEqual(int(result[5:]), id(loop))
            wait_process(pid, exitcode=0)

    @hashlib_helper.requires_hashdigest('md5')
    def test_fork_signal_handling(self):
        self.addCleanup(multiprocessing_cleanup_tests)

        # Sending signal to the forked process should not affect the parent
        # process
        ctx = multiprocessing.get_context('fork')
        manager = ctx.Manager()
        self.addCleanup(manager.shutdown)
        child_started = manager.Event()
        child_handled = manager.Event()
        parent_handled = manager.Event()

        def child_main():
            def on_sigterm(*args):
                child_handled.set()
                sys.exit()

            signal.signal(signal.SIGTERM, on_sigterm)
            child_started.set()
            while True:
                time.sleep(1)

        async def main():
            loop = asyncio.get_running_loop()
            loop.add_signal_handler(signal.SIGTERM, lambda *args: parent_handled.set())

            process = ctx.Process(target=child_main)
            process.start()
            child_started.wait()
            os.kill(process.pid, signal.SIGTERM)
            process.join(timeout=support.SHORT_TIMEOUT)

            async def func():
                await asyncio.sleep(0.1)
                return 42

            # Test parent's loop is still functional
            self.assertEqual(await asyncio.create_task(func()), 42)

        asyncio.run(main())

        child_handled.wait(timeout=support.SHORT_TIMEOUT)
        self.assertFalse(parent_handled.is_set())
        self.assertTrue(child_handled.is_set())

    @hashlib_helper.requires_hashdigest('md5')
    def test_fork_asyncio_run(self):
        self.addCleanup(multiprocessing_cleanup_tests)

        ctx = multiprocessing.get_context('fork')
        manager = ctx.Manager()
        self.addCleanup(manager.shutdown)
        result = manager.Value('i', 0)

        async def child_main():
            await asyncio.sleep(0.1)
            result.value = 42

        process = ctx.Process(target=lambda: asyncio.run(child_main()))
        process.start()
        process.join()

        self.assertEqual(result.value, 42)

    @hashlib_helper.requires_hashdigest('md5')
    def test_fork_asyncio_subprocess(self):
        self.addCleanup(multiprocessing_cleanup_tests)

        ctx = multiprocessing.get_context('fork')
        manager = ctx.Manager()
        self.addCleanup(manager.shutdown)
        result = manager.Value('i', 1)

        async def child_main():
            proc = await asyncio.create_subprocess_exec(sys.executable, '-c', 'pass')
            result.value = await proc.wait()

        process = ctx.Process(target=lambda: asyncio.run(child_main()))
        process.start()
        process.join()

        self.assertEqual(result.value, 0)

if __name__ == '__main__':
    unittest.main()