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.

1 files changed, 4 insertions, 3 deletions

diff --git a/Lib/test/test_smtplib.py b/Lib/test/test_smtplib.py
index 067c01c..d1ffb36 100644
--- a/Lib/test/test_smtplib.py
+++ b/Lib/test/test_smtplib.py
@@ -20,11 +20,12 @@ import threading
 
 import unittest
 from test import support, mock_socket
-from test.support import HOST
+from test.support import socket_helper
 from test.support import threading_setup, threading_cleanup, join_thread
 from test.support import requires_hashdigest
 from unittest.mock import Mock
 
+HOST = socket_helper.HOST
 
 if sys.platform == 'darwin':
     # select.poll returns a select.POLLHUP at the end of the tests
@@ -271,7 +272,7 @@ class DebuggingServerTests(unittest.TestCase):
 
     def testSourceAddress(self):
         # connect
-        src_port = support.find_unused_port()
+        src_port = socket_helper.find_unused_port()
         try:
             smtp = smtplib.SMTP(self.host, self.port, local_hostname='localhost',
                                 timeout=support.LOOPBACK_TIMEOUT,
@@ -711,7 +712,7 @@ class TooLongLineTests(unittest.TestCase):
         self.evt = threading.Event()
         self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         self.sock.settimeout(15)
-        self.port = support.bind_port(self.sock)
+        self.port = socket_helper.bind_port(self.sock)
         servargs = (self.evt, self.respdata, self.sock)
         self.thread = threading.Thread(target=server, args=servargs)
         self.thread.start()