bpo-40275: Avoid importing socket in test.support (GH-19603)

* Move socket related functions from test.support to socket_helper.
* Import socket, nntplib and urllib.error lazily in transient_internet().
* Remove importing multiprocess.

8 files changed, 44 insertions, 37 deletions

diff --git a/Lib/test/test_asyncio/test_base_events.py b/Lib/test/test_asyncio/test_base_events.py
index fc832d3..4adcbf4 100644
--- a/Lib/test/test_asyncio/test_base_events.py
+++ b/Lib/test/test_asyncio/test_base_events.py
@@ -17,6 +17,7 @@ from asyncio import constants
 from test.test_asyncio import utils as test_utils
 from test import support
 from test.support.script_helper import assert_python_ok
+from test.support import socket_helper
 
 
 MOCK_ANY = mock.ANY
@@ -91,7 +92,7 @@ class BaseEventTests(test_utils.TestCase):
         self.assertIsNone(
             base_events._ipaddr_info('1.2.3.4', 1, UNSPEC, 0, 0))
 
-        if support.IPV6_ENABLED:
+        if socket_helper.IPV6_ENABLED:
             # IPv4 address with family IPv6.
             self.assertIsNone(
                 base_events._ipaddr_info('1.2.3.4', 1, INET6, STREAM, TCP))
@@ -1156,7 +1157,7 @@ class BaseEventLoopWithSelectorTests(test_utils.TestCase):
             srv.close()
             self.loop.run_until_complete(srv.wait_closed())
 
-    @unittest.skipUnless(support.IPV6_ENABLED, 'no IPv6 support')
+    @unittest.skipUnless(socket_helper.IPV6_ENABLED, 'no IPv6 support')
     def test_create_server_ipv6(self):
         async def main():
             with self.assertWarns(DeprecationWarning):
@@ -1288,7 +1289,7 @@ class BaseEventLoopWithSelectorTests(test_utils.TestCase):
             t.close()
             test_utils.run_briefly(self.loop)  # allow transport to close
 
-        if support.IPV6_ENABLED:
+        if socket_helper.IPV6_ENABLED:
             sock.family = socket.AF_INET6
             coro = self.loop.create_connection(asyncio.Protocol, '::1', 80)
             t, p = self.loop.run_until_complete(coro)
@@ -1307,7 +1308,7 @@ class BaseEventLoopWithSelectorTests(test_utils.TestCase):
                 t.close()
                 test_utils.run_briefly(self.loop)  # allow transport to close
 
-    @unittest.skipUnless(support.IPV6_ENABLED, 'no IPv6 support')
+    @unittest.skipUnless(socket_helper.IPV6_ENABLED, 'no IPv6 support')
     @unittest.skipIf(sys.platform.startswith('aix'),
                     "bpo-25545: IPv6 scope id and getaddrinfo() behave differently on AIX")
     @patch_socket
@@ -1639,7 +1640,7 @@ class BaseEventLoopWithSelectorTests(test_utils.TestCase):
         self.assertRaises(
             OSError, self.loop.run_until_complete, coro)
 
-    @unittest.skipUnless(support.IPV6_ENABLED, 'IPv6 not supported or enabled')
+    @unittest.skipUnless(socket_helper.IPV6_ENABLED, 'IPv6 not supported or enabled')
     def test_create_datagram_endpoint_no_matching_family(self):
         coro = self.loop.create_datagram_endpoint(
             asyncio.DatagramProtocol,
@@ -1700,7 +1701,7 @@ class BaseEventLoopWithSelectorTests(test_utils.TestCase):
         self.loop.run_until_complete(protocol.done)
         self.assertEqual('CLOSED', protocol.state)
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     def test_create_datagram_endpoint_existing_sock_unix(self):
         with test_utils.unix_socket_path() as path:
             sock = socket.socket(socket.AF_UNIX, type=socket.SOCK_DGRAM)
@@ -2015,7 +2016,7 @@ class BaseLoopSockSendfileTests(test_utils.TestCase):
         sock = self.make_socket()
         proto = self.MyProto(self.loop)
         server = self.run_loop(self.loop.create_server(
-            lambda: proto, support.HOST, 0, family=socket.AF_INET))
+            lambda: proto, socket_helper.HOST, 0, family=socket.AF_INET))
         addr = server.sockets[0].getsockname()
 
         for _ in range(10):
diff --git a/Lib/test/test_asyncio/test_events.py b/Lib/test/test_asyncio/test_events.py
index 1f71c1f..aa4daca 100644
--- a/Lib/test/test_asyncio/test_events.py
+++ b/Lib/test/test_asyncio/test_events.py
@@ -32,6 +32,7 @@ from asyncio import proactor_events
 from asyncio import selector_events
 from test.test_asyncio import utils as test_utils
 from test import support
+from test.support import socket_helper
 from test.support import ALWAYS_EQ, LARGEST, SMALLEST
 
 
@@ -517,7 +518,7 @@ class EventLoopTestsMixin:
                 lambda: MyProto(loop=self.loop), *httpd.address)
             self._basetest_create_connection(conn_fut)
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     def test_create_unix_connection(self):
         # Issue #20682: On Mac OS X Tiger, getsockname() returns a
         # zero-length address for UNIX socket.
@@ -619,7 +620,7 @@ class EventLoopTestsMixin:
             self._test_create_ssl_connection(httpd, create_connection,
                                              peername=httpd.address)
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     @unittest.skipIf(ssl is None, 'No ssl module')
     def test_create_ssl_unix_connection(self):
         # Issue #20682: On Mac OS X Tiger, getsockname() returns a
@@ -638,7 +639,7 @@ class EventLoopTestsMixin:
 
     def test_create_connection_local_addr(self):
         with test_utils.run_test_server() as httpd:
-            port = support.find_unused_port()
+            port = socket_helper.find_unused_port()
             f = self.loop.create_connection(
                 lambda: MyProto(loop=self.loop),
                 *httpd.address, local_addr=(httpd.address[0], port))
@@ -843,7 +844,7 @@ class EventLoopTestsMixin:
 
         return server, path
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     def test_create_unix_server(self):
         proto = MyProto(loop=self.loop)
         server, path = self._make_unix_server(lambda: proto)
@@ -935,7 +936,7 @@ class EventLoopTestsMixin:
         # stop serving
         server.close()
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     @unittest.skipIf(ssl is None, 'No ssl module')
     def test_create_unix_server_ssl(self):
         proto = MyProto(loop=self.loop)
@@ -995,7 +996,7 @@ class EventLoopTestsMixin:
         self.assertIsNone(proto.transport)
         server.close()
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     @unittest.skipIf(ssl is None, 'No ssl module')
     def test_create_unix_server_ssl_verify_failed(self):
         proto = MyProto(loop=self.loop)
@@ -1055,7 +1056,7 @@ class EventLoopTestsMixin:
         self.assertIsNone(proto.transport)
         server.close()
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     @unittest.skipIf(ssl is None, 'No ssl module')
     def test_create_unix_server_ssl_verified(self):
         proto = MyProto(loop=self.loop)
@@ -1148,7 +1149,7 @@ class EventLoopTestsMixin:
 
         server.close()
 
-    @unittest.skipUnless(support.IPV6_ENABLED, 'IPv6 not supported or enabled')
+    @unittest.skipUnless(socket_helper.IPV6_ENABLED, 'IPv6 not supported or enabled')
     def test_create_server_dual_stack(self):
         f_proto = self.loop.create_future()
 
@@ -1160,7 +1161,7 @@ class EventLoopTestsMixin:
         try_count = 0
         while True:
             try:
-                port = support.find_unused_port()
+                port = socket_helper.find_unused_port()
                 f = self.loop.create_server(TestMyProto, host=None, port=port)
                 server = self.loop.run_until_complete(f)
             except OSError as ex:
diff --git a/Lib/test/test_asyncio/test_proactor_events.py b/Lib/test/test_asyncio/test_proactor_events.py
index 007039a..b5d1df9 100644
--- a/Lib/test/test_asyncio/test_proactor_events.py
+++ b/Lib/test/test_asyncio/test_proactor_events.py
@@ -13,6 +13,7 @@ from asyncio.proactor_events import _ProactorWritePipeTransport
 from asyncio.proactor_events import _ProactorDuplexPipeTransport
 from asyncio.proactor_events import _ProactorDatagramTransport
 from test import support
+from test.support import socket_helper
 from test.test_asyncio import utils as test_utils
 
 
@@ -950,7 +951,7 @@ class ProactorEventLoopUnixSockSendfileTests(test_utils.TestCase):
     def prepare(self):
         sock = self.make_socket()
         proto = self.MyProto(self.loop)
-        port = support.find_unused_port()
+        port = socket_helper.find_unused_port()
         srv_sock = self.make_socket(cleanup=False)
         srv_sock.bind(('127.0.0.1', port))
         server = self.run_loop(self.loop.create_server(
diff --git a/Lib/test/test_asyncio/test_sendfile.py b/Lib/test/test_asyncio/test_sendfile.py
index 3b7f784..dbce199 100644
--- a/Lib/test/test_asyncio/test_sendfile.py
+++ b/Lib/test/test_asyncio/test_sendfile.py
@@ -10,6 +10,7 @@ from asyncio import base_events
 from asyncio import constants
 from unittest import mock
 from test import support
+from test.support import socket_helper
 from test.test_asyncio import utils as test_utils
 
 try:
@@ -163,9 +164,9 @@ class SockSendfileMixin(SendfileBase):
 
     def prepare_socksendfile(self):
         proto = MyProto(self.loop)
-        port = support.find_unused_port()
+        port = socket_helper.find_unused_port()
         srv_sock = self.make_socket(cleanup=False)
-        srv_sock.bind((support.HOST, port))
+        srv_sock.bind((socket_helper.HOST, port))
         server = self.run_loop(self.loop.create_server(
             lambda: proto, sock=srv_sock))
         self.reduce_receive_buffer_size(srv_sock)
@@ -240,7 +241,7 @@ class SendfileMixin(SendfileBase):
     # Note: sendfile via SSL transport is equal to sendfile fallback
 
     def prepare_sendfile(self, *, is_ssl=False, close_after=0):
-        port = support.find_unused_port()
+        port = socket_helper.find_unused_port()
         srv_proto = MySendfileProto(loop=self.loop,
                                     close_after=close_after)
         if is_ssl:
@@ -252,17 +253,17 @@ class SendfileMixin(SendfileBase):
             srv_ctx = None
             cli_ctx = None
         srv_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        srv_sock.bind((support.HOST, port))
+        srv_sock.bind((socket_helper.HOST, port))
         server = self.run_loop(self.loop.create_server(
             lambda: srv_proto, sock=srv_sock, ssl=srv_ctx))
         self.reduce_receive_buffer_size(srv_sock)
 
         if is_ssl:
-            server_hostname = support.HOST
+            server_hostname = socket_helper.HOST
         else:
             server_hostname = None
         cli_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        cli_sock.connect((support.HOST, port))
+        cli_sock.connect((socket_helper.HOST, port))
 
         cli_proto = MySendfileProto(loop=self.loop)
         tr, pr = self.run_loop(self.loop.create_connection(
diff --git a/Lib/test/test_asyncio/test_server.py b/Lib/test/test_asyncio/test_server.py
index d47ccc0..006ead2 100644
--- a/Lib/test/test_asyncio/test_server.py
+++ b/Lib/test/test_asyncio/test_server.py
@@ -4,6 +4,7 @@ import threading
 import unittest
 
 from test import support
+from test.support import socket_helper
 from test.test_asyncio import utils as test_utils
 from test.test_asyncio import functional as func_tests
 
@@ -47,7 +48,7 @@ class BaseStartServer(func_tests.FunctionalTestCaseMixin):
 
         with self.assertWarns(DeprecationWarning):
             srv = self.loop.run_until_complete(asyncio.start_server(
-                serve, support.HOSTv4, 0, loop=self.loop, start_serving=False))
+                serve, socket_helper.HOSTv4, 0, loop=self.loop, start_serving=False))
 
         self.assertFalse(srv.is_serving())
 
@@ -73,7 +74,7 @@ class SelectorStartServerTests(BaseStartServer, unittest.TestCase):
     def new_loop(self):
         return asyncio.SelectorEventLoop()
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     def test_start_unix_server_1(self):
         HELLO_MSG = b'1' * 1024 * 5 + b'\n'
         started = threading.Event()
diff --git a/Lib/test/test_asyncio/test_sock_lowlevel.py b/Lib/test/test_asyncio/test_sock_lowlevel.py
index 89c2af9..2f2d5a4 100644
--- a/Lib/test/test_asyncio/test_sock_lowlevel.py
+++ b/Lib/test/test_asyncio/test_sock_lowlevel.py
@@ -5,6 +5,7 @@ from asyncio import proactor_events
 from itertools import cycle, islice
 from test.test_asyncio import utils as test_utils
 from test import support
+from test.support import socket_helper
 
 
 class MyProto(asyncio.Protocol):
@@ -225,7 +226,7 @@ class BaseSockTestsMixin:
             self.loop.run_until_complete(
                 self._basetest_huge_content_recvinto(httpd.address))
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     def test_unix_sock_client_ops(self):
         with test_utils.run_test_unix_server() as httpd:
             sock = socket.socket(socket.AF_UNIX)
diff --git a/Lib/test/test_asyncio/test_streams.py b/Lib/test/test_asyncio/test_streams.py
index 12bd536..1e9d115 100644
--- a/Lib/test/test_asyncio/test_streams.py
+++ b/Lib/test/test_asyncio/test_streams.py
@@ -9,7 +9,7 @@ import sys
 import threading
 import unittest
 from unittest import mock
-from test import support
+from test.support import socket_helper
 try:
     import ssl
 except ImportError:
@@ -66,7 +66,7 @@ class StreamTests(test_utils.TestCase):
                                                loop=self.loop)
             self._basetest_open_connection(conn_fut)
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     def test_open_unix_connection(self):
         with test_utils.run_test_unix_server() as httpd:
             conn_fut = asyncio.open_unix_connection(httpd.address,
@@ -99,7 +99,7 @@ class StreamTests(test_utils.TestCase):
 
             self._basetest_open_connection_no_loop_ssl(conn_fut)
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     @unittest.skipIf(ssl is None, 'No ssl module')
     def test_open_unix_connection_no_loop_ssl(self):
         with test_utils.run_test_unix_server(use_ssl=True) as httpd:
@@ -130,7 +130,7 @@ class StreamTests(test_utils.TestCase):
                                                loop=self.loop)
             self._basetest_open_connection_error(conn_fut)
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     def test_open_unix_connection_error(self):
         with test_utils.run_test_unix_server() as httpd:
             conn_fut = asyncio.open_unix_connection(httpd.address,
@@ -653,7 +653,7 @@ class StreamTests(test_utils.TestCase):
 
         self.assertEqual(messages, [])
 
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     def test_start_unix_server(self):
 
         class MyServer:
diff --git a/Lib/test/test_asyncio/test_unix_events.py b/Lib/test/test_asyncio/test_unix_events.py
index 5487b7a..10bd46d 100644
--- a/Lib/test/test_asyncio/test_unix_events.py
+++ b/Lib/test/test_asyncio/test_unix_events.py
@@ -15,6 +15,7 @@ import threading
 import unittest
 from unittest import mock
 from test import support
+from test.support import socket_helper
 
 if sys.platform == 'win32':
     raise unittest.SkipTest('UNIX only')
@@ -273,7 +274,7 @@ class SelectorEventLoopUnixSocketTests(test_utils.TestCase):
         self.loop = asyncio.SelectorEventLoop()
         self.set_event_loop(self.loop)
 
-    @support.skip_unless_bind_unix_socket
+    @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)
@@ -286,7 +287,7 @@ class SelectorEventLoopUnixSocketTests(test_utils.TestCase):
             srv.close()
             self.loop.run_until_complete(srv.wait_closed())
 
-    @support.skip_unless_bind_unix_socket
+    @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)
@@ -344,7 +345,7 @@ class SelectorEventLoopUnixSocketTests(test_utils.TestCase):
 
     @unittest.skipUnless(hasattr(socket, 'SOCK_NONBLOCK'),
                          'no socket.SOCK_NONBLOCK (linux only)')
-    @support.skip_unless_bind_unix_socket
+    @socket_helper.skip_unless_bind_unix_socket
     def test_create_unix_server_path_stream_bittype(self):
         sock = socket.socket(
             socket.AF_UNIX, socket.SOCK_STREAM | socket.SOCK_NONBLOCK)
@@ -497,12 +498,12 @@ class SelectorEventLoopUnixSockSendfileTests(test_utils.TestCase):
     def prepare(self):
         sock = self.make_socket()
         proto = self.MyProto(self.loop)
-        port = support.find_unused_port()
+        port = socket_helper.find_unused_port()
         srv_sock = self.make_socket(cleanup=False)
-        srv_sock.bind((support.HOST, port))
+        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, (support.HOST, port)))
+        self.run_loop(self.loop.sock_connect(sock, (socket_helper.HOST, port)))
         self.run_loop(proto._ready)
 
         def cleanup():