- Issue #2550: The approach used by client/server code for obtaining ports

  to listen on in network-oriented tests has been refined in an effort to
  facilitate running multiple instances of the entire regression test suite
  in parallel without issue.  test_support.bind_port() has been fixed such
  that it will always return a unique port -- which wasn't always the case
  with the previous implementation, especially if socket options had been
  set that affected address reuse (i.e. SO_REUSEADDR, SO_REUSEPORT).  The
  new implementation of bind_port() will actually raise an exception if it
  is passed an AF_INET/SOCK_STREAM socket with either the SO_REUSEADDR or
  SO_REUSEPORT socket option set.  Furthermore, if available, bind_port()
  will set the SO_EXCLUSIVEADDRUSE option on the socket it's been passed.
  This currently only applies to Windows.  This option prevents any other
  sockets from binding to the host/port we've bound to, thus removing the
  possibility of the 'non-deterministic' behaviour, as Microsoft puts it,
  that occurs when a second SOCK_STREAM socket binds and accepts to a
  host/port that's already been bound by another socket.  The optional
  preferred port parameter to bind_port() has been removed.  Under no
  circumstances should tests be hard coding ports!

  test_support.find_unused_port() has also been introduced, which will pass
  a temporary socket object to bind_port() in order to obtain an unused port.
  The temporary socket object is then closed and deleted, and the port is
  returned.  This method should only be used for obtaining an unused port
  in order to pass to an external program (i.e. the -accept [port] argument
  to openssl's s_server mode) or as a parameter to a server-oriented class
  that doesn't give you direct access to the underlying socket used.

  Finally, test_support.HOST has been introduced, which should be used for
  the host argument of any relevant socket calls (i.e. bind and connect).

  The following tests were updated to following the new conventions:
    test_socket, test_smtplib, test_asyncore, test_ssl, test_httplib,
    test_poplib, test_ftplib, test_telnetlib, test_socketserver,
    test_asynchat and test_socket_ssl.

  It is now possible for multiple instances of the regression test suite to
  run in parallel without issue.

13 files changed, 716 insertions, 651 deletions

diff --git a/Lib/test/test_asynchat.py b/Lib/test/test_asynchat.py
index 4c79458..5501c2d 100644
--- a/Lib/test/test_asynchat.py
+++ b/Lib/test/test_asynchat.py
@@ -6,8 +6,7 @@ import unittest
 import sys
 from test import test_support
 
-HOST = "127.0.0.1"
-PORT = 54322
+HOST = test_support.HOST
 SERVER_QUIT = 'QUIT\n'
 
 class echo_server(threading.Thread):
@@ -18,15 +17,13 @@ class echo_server(threading.Thread):
     def __init__(self, event):
         threading.Thread.__init__(self)
         self.event = event
+        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.port = test_support.bind_port(self.sock)
 
     def run(self):
-        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-        global PORT
-        PORT = test_support.bind_port(sock, HOST, PORT)
-        sock.listen(1)
+        self.sock.listen(1)
         self.event.set()
-        conn, client = sock.accept()
+        conn, client = self.sock.accept()
         self.buffer = ""
         # collect data until quit message is seen
         while SERVER_QUIT not in self.buffer:
@@ -50,15 +47,15 @@ class echo_server(threading.Thread):
             pass
 
         conn.close()
-        sock.close()
+        self.sock.close()
 
 class echo_client(asynchat.async_chat):
 
-    def __init__(self, terminator):
+    def __init__(self, terminator, server_port):
         asynchat.async_chat.__init__(self)
         self.contents = []
         self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
-        self.connect((HOST, PORT))
+        self.connect((HOST, server_port))
         self.set_terminator(terminator)
         self.buffer = ''
 
@@ -106,7 +103,7 @@ class TestAsynchat(unittest.TestCase):
         event.wait()
         event.clear()
         time.sleep(0.01) # Give server time to start accepting.
-        c = echo_client(term)
+        c = echo_client(term, s.port)
         c.push("hello ")
         c.push("world%s" % term)
         c.push("I'm not dead yet!%s" % term)
@@ -138,7 +135,7 @@ class TestAsynchat(unittest.TestCase):
     def numeric_terminator_check(self, termlen):
         # Try reading a fixed number of bytes
         s, event = start_echo_server()
-        c = echo_client(termlen)
+        c = echo_client(termlen, s.port)
         data = "hello world, I'm not dead yet!\n"
         c.push(data)
         c.push(SERVER_QUIT)
@@ -159,7 +156,7 @@ class TestAsynchat(unittest.TestCase):
     def test_none_terminator(self):
         # Try reading a fixed number of bytes
         s, event = start_echo_server()
-        c = echo_client(None)
+        c = echo_client(None, s.port)
         data = "hello world, I'm not dead yet!\n"
         c.push(data)
         c.push(SERVER_QUIT)
@@ -171,7 +168,7 @@ class TestAsynchat(unittest.TestCase):
 
     def test_simple_producer(self):
         s, event = start_echo_server()
-        c = echo_client('\n')
+        c = echo_client('\n', s.port)
         data = "hello world\nI'm not dead yet!\n"
         p = asynchat.simple_producer(data+SERVER_QUIT, buffer_size=8)
         c.push_with_producer(p)
@@ -182,7 +179,7 @@ class TestAsynchat(unittest.TestCase):
 
     def test_string_producer(self):
         s, event = start_echo_server()
-        c = echo_client('\n')
+        c = echo_client('\n', s.port)
         data = "hello world\nI'm not dead yet!\n"
         c.push_with_producer(data+SERVER_QUIT)
         asyncore.loop(use_poll=self.usepoll, count=300, timeout=.01)
@@ -193,7 +190,7 @@ class TestAsynchat(unittest.TestCase):
     def test_empty_line(self):
         # checks that empty lines are handled correctly
         s, event = start_echo_server()
-        c = echo_client('\n')
+        c = echo_client('\n', s.port)
         c.push("hello world\n\nI'm not dead yet!\n")
         c.push(SERVER_QUIT)
         asyncore.loop(use_poll=self.usepoll, count=300, timeout=.01)
@@ -203,7 +200,7 @@ class TestAsynchat(unittest.TestCase):
 
     def test_close_when_done(self):
         s, event = start_echo_server()
-        c = echo_client('\n')
+        c = echo_client('\n', s.port)
         c.push("hello world\nI'm not dead yet!\n")
         c.push(SERVER_QUIT)
         c.close_when_done()
diff --git a/Lib/test/test_asyncore.py b/Lib/test/test_asyncore.py
index f19ff35..5fa7555 100644
--- a/Lib/test/test_asyncore.py
+++ b/Lib/test/test_asyncore.py
@@ -1,421 +1,412 @@
-import asyncore
-import unittest
-import select
-import os
-import socket
-import threading
-import sys
-import time
-
-from test import test_support
-from test.test_support import TESTFN, run_unittest, unlink
-from StringIO import StringIO
-
-HOST = "127.0.0.1"
-PORT = None
-
-class dummysocket:
-    def __init__(self):
-        self.closed = False
-
-    def close(self):
-        self.closed = True
-
-    def fileno(self):
-        return 42
-
-class dummychannel:
-    def __init__(self):
-        self.socket = dummysocket()
-
-class exitingdummy:
-    def __init__(self):
-        pass
-
-    def handle_read_event(self):
-        raise asyncore.ExitNow()
-
-    handle_write_event = handle_read_event
-    handle_expt_event = handle_read_event
-
-class crashingdummy:
-    def __init__(self):
-        self.error_handled = False
-
-    def handle_read_event(self):
-        raise Exception()
-
-    handle_write_event = handle_read_event
-    handle_expt_event = handle_read_event
-
-    def handle_error(self):
-        self.error_handled = True
-
-# used when testing senders; just collects what it gets until newline is sent
-def capture_server(evt, buf):
-    try:
-        serv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        serv.settimeout(3)
-        serv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-        serv.bind(("", 0))
-        global PORT
-        PORT = serv.getsockname()[1]
-        serv.listen(5)
-        conn, addr = serv.accept()
-    except socket.timeout:
-        pass
-    else:
-        n = 200
-        while n > 0:
-            r, w, e = select.select([conn], [], [])
-            if r:
-                data = conn.recv(10)
-                # keep everything except for the newline terminator
-                buf.write(data.replace('\n', ''))
-                if '\n' in data:
-                    break
-            n -= 1
-            time.sleep(0.01)
-
-        conn.close()
-    finally:
-        serv.close()
-        PORT = None
-        evt.set()
-
-
-class HelperFunctionTests(unittest.TestCase):
-    def test_readwriteexc(self):
-        # Check exception handling behavior of read, write and _exception
-
-        # check that ExitNow exceptions in the object handler method
-        # bubbles all the way up through asyncore read/write/_exception calls
-        tr1 = exitingdummy()
-        self.assertRaises(asyncore.ExitNow, asyncore.read, tr1)
-        self.assertRaises(asyncore.ExitNow, asyncore.write, tr1)
-        self.assertRaises(asyncore.ExitNow, asyncore._exception, tr1)
-
-        # check that an exception other than ExitNow in the object handler
-        # method causes the handle_error method to get called
-        tr2 = crashingdummy()
-        asyncore.read(tr2)
-        self.assertEqual(tr2.error_handled, True)
-
-        tr2 = crashingdummy()
-        asyncore.write(tr2)
-        self.assertEqual(tr2.error_handled, True)
-
-        tr2 = crashingdummy()
-        asyncore._exception(tr2)
-        self.assertEqual(tr2.error_handled, True)
-
-    # asyncore.readwrite uses constants in the select module that
-    # are not present in Windows systems (see this thread:
-    # http://mail.python.org/pipermail/python-list/2001-October/109973.html)
-    # These constants should be present as long as poll is available
-
-    if hasattr(select, 'poll'):
-        def test_readwrite(self):
-            # Check that correct methods are called by readwrite()
-
-            class testobj:
-                def __init__(self):
-                    self.read = False
-                    self.write = False
-                    self.expt = False
-
-                def handle_read_event(self):
-                    self.read = True
-
-                def handle_write_event(self):
-                    self.write = True
-
-                def handle_expt_event(self):
-                    self.expt = True
-
-                def handle_error(self):
-                    self.error_handled = True
-
-            for flag in (select.POLLIN, select.POLLPRI):
-                tobj = testobj()
-                self.assertEqual(tobj.read, False)
-                asyncore.readwrite(tobj, flag)
-                self.assertEqual(tobj.read, True)
-
-                # check that ExitNow exceptions in the object handler method
-                # bubbles all the way up through asyncore readwrite call
-                tr1 = exitingdummy()
-                self.assertRaises(asyncore.ExitNow, asyncore.readwrite, tr1, flag)
-
-                # check that an exception other than ExitNow in the object handler
-                # method causes the handle_error method to get called
-                tr2 = crashingdummy()
-                asyncore.readwrite(tr2, flag)
-                self.assertEqual(tr2.error_handled, True)
-
-            tobj = testobj()
-            self.assertEqual(tobj.write, False)
-            asyncore.readwrite(tobj, select.POLLOUT)
-            self.assertEqual(tobj.write, True)
-
-            # check that ExitNow exceptions in the object handler method
-            # bubbles all the way up through asyncore readwrite call
-            tr1 = exitingdummy()
-            self.assertRaises(asyncore.ExitNow, asyncore.readwrite, tr1,
-                              select.POLLOUT)
-
-            # check that an exception other than ExitNow in the object handler
-            # method causes the handle_error method to get called
-            tr2 = crashingdummy()
-            asyncore.readwrite(tr2, select.POLLOUT)
-            self.assertEqual(tr2.error_handled, True)
-
-            for flag in (select.POLLERR, select.POLLHUP, select.POLLNVAL):
-                tobj = testobj()
-                self.assertEqual(tobj.expt, False)
-                asyncore.readwrite(tobj, flag)
-                self.assertEqual(tobj.expt, True)
-
-                # check that ExitNow exceptions in the object handler method
-                # bubbles all the way up through asyncore readwrite calls
-                tr1 = exitingdummy()
-                self.assertRaises(asyncore.ExitNow, asyncore.readwrite, tr1, flag)
-
-                # check that an exception other than ExitNow in the object handler
-                # method causes the handle_error method to get called
-                tr2 = crashingdummy()
-                asyncore.readwrite(tr2, flag)
-                self.assertEqual(tr2.error_handled, True)
-
-    def test_closeall(self):
-        self.closeall_check(False)
-
-    def test_closeall_default(self):
-        self.closeall_check(True)
-
-    def closeall_check(self, usedefault):
-        # Check that close_all() closes everything in a given map
-
-        l = []
-        testmap = {}
-        for i in range(10):
-            c = dummychannel()
-            l.append(c)
-            self.assertEqual(c.socket.closed, False)
-            testmap[i] = c
-
-        if usedefault:
-            socketmap = asyncore.socket_map
-            try:
-                asyncore.socket_map = testmap
-                asyncore.close_all()
-            finally:
-                testmap, asyncore.socket_map = asyncore.socket_map, socketmap
-        else:
-            asyncore.close_all(testmap)
-
-        self.assertEqual(len(testmap), 0)
-
-        for c in l:
-            self.assertEqual(c.socket.closed, True)
-
-    def test_compact_traceback(self):
-        try:
-            raise Exception("I don't like spam!")
-        except:
-            real_t, real_v, real_tb = sys.exc_info()
-            r = asyncore.compact_traceback()
-        else:
-            self.fail("Expected exception")
-
-        (f, function, line), t, v, info = r
-        self.assertEqual(os.path.split(f)[-1], 'test_asyncore.py')
-        self.assertEqual(function, 'test_compact_traceback')
-        self.assertEqual(t, real_t)
-        self.assertEqual(v, real_v)
-        self.assertEqual(info, '[%s|%s|%s]' % (f, function, line))
-
-
-class DispatcherTests(unittest.TestCase):
-    def setUp(self):
-        pass
-
-    def tearDown(self):
-        asyncore.close_all()
-
-    def test_basic(self):
-        d = asyncore.dispatcher()
-        self.assertEqual(d.readable(), True)
-        self.assertEqual(d.writable(), True)
-
-    def test_repr(self):
-        d = asyncore.dispatcher()
-        self.assertEqual(repr(d), '<asyncore.dispatcher at %#x>' % id(d))
-
-    def test_log(self):
-        d = asyncore.dispatcher()
-
-        # capture output of dispatcher.log() (to stderr)
-        fp = StringIO()
-        stderr = sys.stderr
-        l1 = "Lovely spam! Wonderful spam!"
-        l2 = "I don't like spam!"
-        try:
-            sys.stderr = fp
-            d.log(l1)
-            d.log(l2)
-        finally:
-            sys.stderr = stderr
-
-        lines = fp.getvalue().splitlines()
-        self.assertEquals(lines, ['log: %s' % l1, 'log: %s' % l2])
-
-    def test_log_info(self):
-        d = asyncore.dispatcher()
-
-        # capture output of dispatcher.log_info() (to stdout via print)
-        fp = StringIO()
-        stdout = sys.stdout
-        l1 = "Have you got anything without spam?"
-        l2 = "Why can't she have egg bacon spam and sausage?"
-        l3 = "THAT'S got spam in it!"
-        try:
-            sys.stdout = fp
-            d.log_info(l1, 'EGGS')
-            d.log_info(l2)
-            d.log_info(l3, 'SPAM')
-        finally:
-            sys.stdout = stdout
-
-        lines = fp.getvalue().splitlines()
-        if __debug__:
-            expected = ['EGGS: %s' % l1, 'info: %s' % l2, 'SPAM: %s' % l3]
-        else:
-            expected = ['EGGS: %s' % l1, 'SPAM: %s' % l3]
-
-        self.assertEquals(lines, expected)
-
-    def test_unhandled(self):
-        d = asyncore.dispatcher()
-
-        # capture output of dispatcher.log_info() (to stdout via print)
-        fp = StringIO()
-        stdout = sys.stdout
-        try:
-            sys.stdout = fp
-            d.handle_expt()
-            d.handle_read()
-            d.handle_write()
-            d.handle_connect()
-            d.handle_accept()
-        finally:
-            sys.stdout = stdout
-
-        lines = fp.getvalue().splitlines()
-        expected = ['warning: unhandled exception',
-                    'warning: unhandled read event',
-                    'warning: unhandled write event',
-                    'warning: unhandled connect event',
-                    'warning: unhandled accept event']
-        self.assertEquals(lines, expected)
-
-
-
-class dispatcherwithsend_noread(asyncore.dispatcher_with_send):
-    def readable(self):
-        return False
-
-    def handle_connect(self):
-        pass
-
-class DispatcherWithSendTests(unittest.TestCase):
-    usepoll = False
-
-    def setUp(self):
-        pass
-
-    def tearDown(self):
-        asyncore.close_all()
-
-    def test_send(self):
-        self.evt = threading.Event()
-        cap = StringIO()
-        threading.Thread(target=capture_server, args=(self.evt,cap)).start()
-
-        # wait until server thread has assigned a port number
-        n = 1000
-        while PORT is None and n > 0:
-            time.sleep(0.01)
-            n -= 1
-
-        # wait a little longer for the server to initialize (it sometimes
-        # refuses connections on slow machines without this wait)
-        time.sleep(0.2)
-
-        data = "Suppose there isn't a 16-ton weight?"
-        d = dispatcherwithsend_noread()
-        d.create_socket(socket.AF_INET, socket.SOCK_STREAM)
-        d.connect((HOST, PORT))
-
-        # give time for socket to connect
-        time.sleep(0.1)
-
-        d.send(data)
-        d.send(data)
-        d.send('\n')
-
-        n = 1000
-        while d.out_buffer and n > 0:
-            asyncore.poll()
-            n -= 1
-
-        self.evt.wait()
-
-        self.assertEqual(cap.getvalue(), data*2)
-
-
-class DispatcherWithSendTests_UsePoll(DispatcherWithSendTests):
-    usepoll = True
-
-if hasattr(asyncore, 'file_wrapper'):
-    class FileWrapperTest(unittest.TestCase):
-        def setUp(self):
-            self.d = "It's not dead, it's sleeping!"
-            file(TESTFN, 'w').write(self.d)
-
-        def tearDown(self):
-            unlink(TESTFN)
-
-        def test_recv(self):
-            fd = os.open(TESTFN, os.O_RDONLY)
-            w = asyncore.file_wrapper(fd)
-
-            self.assertEqual(w.fd, fd)
-            self.assertEqual(w.fileno(), fd)
-            self.assertEqual(w.recv(13), "It's not dead")
-            self.assertEqual(w.read(6), ", it's")
-            w.close()
-            self.assertRaises(OSError, w.read, 1)
-
-        def test_send(self):
-            d1 = "Come again?"
-            d2 = "I want to buy some cheese."
-            fd = os.open(TESTFN, os.O_WRONLY | os.O_APPEND)
-            w = asyncore.file_wrapper(fd)
-
-            w.write(d1)
-            w.send(d2)
-            w.close()
-            self.assertEqual(file(TESTFN).read(), self.d + d1 + d2)
-
-
-def test_main():
-    tests = [HelperFunctionTests, DispatcherTests, DispatcherWithSendTests,
-             DispatcherWithSendTests_UsePoll]
-    if hasattr(asyncore, 'file_wrapper'):
-        tests.append(FileWrapperTest)
-
-    run_unittest(*tests)
-
-if __name__ == "__main__":
-    test_main()
+import asyncore

+import unittest

+import select

+import os

+import socket

+import threading

+import sys

+import time

+

+from test import test_support

+from test.test_support import TESTFN, run_unittest, unlink

+from StringIO import StringIO

+

+HOST = test_support.HOST

+

+class dummysocket:

+    def __init__(self):

+        self.closed = False

+

+    def close(self):

+        self.closed = True

+

+    def fileno(self):

+        return 42

+

+class dummychannel:

+    def __init__(self):

+        self.socket = dummysocket()

+

+class exitingdummy:

+    def __init__(self):

+        pass

+

+    def handle_read_event(self):

+        raise asyncore.ExitNow()

+

+    handle_write_event = handle_read_event

+    handle_expt_event = handle_read_event

+

+class crashingdummy:

+    def __init__(self):

+        self.error_handled = False

+

+    def handle_read_event(self):

+        raise Exception()

+

+    handle_write_event = handle_read_event

+    handle_expt_event = handle_read_event

+

+    def handle_error(self):

+        self.error_handled = True

+

+# used when testing senders; just collects what it gets until newline is sent

+def capture_server(evt, buf, serv):

+    try:

+        serv.listen(5)

+        conn, addr = serv.accept()

+    except socket.timeout:

+        pass

+    else:

+        n = 200

+        while n > 0:

+            r, w, e = select.select([conn], [], [])

+            if r:

+                data = conn.recv(10)

+                # keep everything except for the newline terminator

+                buf.write(data.replace('\n', ''))

+                if '\n' in data:

+                    break

+            n -= 1

+            time.sleep(0.01)

+

+        conn.close()

+    finally:

+        serv.close()

+        evt.set()

+

+

+class HelperFunctionTests(unittest.TestCase):

+    def test_readwriteexc(self):

+        # Check exception handling behavior of read, write and _exception

+

+        # check that ExitNow exceptions in the object handler method

+        # bubbles all the way up through asyncore read/write/_exception calls

+        tr1 = exitingdummy()

+        self.assertRaises(asyncore.ExitNow, asyncore.read, tr1)

+        self.assertRaises(asyncore.ExitNow, asyncore.write, tr1)

+        self.assertRaises(asyncore.ExitNow, asyncore._exception, tr1)

+

+        # check that an exception other than ExitNow in the object handler

+        # method causes the handle_error method to get called

+        tr2 = crashingdummy()

+        asyncore.read(tr2)

+        self.assertEqual(tr2.error_handled, True)

+

+        tr2 = crashingdummy()

+        asyncore.write(tr2)

+        self.assertEqual(tr2.error_handled, True)

+

+        tr2 = crashingdummy()

+        asyncore._exception(tr2)

+        self.assertEqual(tr2.error_handled, True)

+

+    # asyncore.readwrite uses constants in the select module that

+    # are not present in Windows systems (see this thread:

+    # http://mail.python.org/pipermail/python-list/2001-October/109973.html)

+    # These constants should be present as long as poll is available

+

+    if hasattr(select, 'poll'):

+        def test_readwrite(self):

+            # Check that correct methods are called by readwrite()

+

+            class testobj:

+                def __init__(self):

+                    self.read = False

+                    self.write = False

+                    self.expt = False

+

+                def handle_read_event(self):

+                    self.read = True

+

+                def handle_write_event(self):

+                    self.write = True

+

+                def handle_expt_event(self):

+                    self.expt = True

+

+                def handle_error(self):

+                    self.error_handled = True

+

+            for flag in (select.POLLIN, select.POLLPRI):

+                tobj = testobj()

+                self.assertEqual(tobj.read, False)

+                asyncore.readwrite(tobj, flag)

+                self.assertEqual(tobj.read, True)

+

+                # check that ExitNow exceptions in the object handler method

+                # bubbles all the way up through asyncore readwrite call

+                tr1 = exitingdummy()

+                self.assertRaises(asyncore.ExitNow, asyncore.readwrite, tr1, flag)

+

+                # check that an exception other than ExitNow in the object handler

+                # method causes the handle_error method to get called

+                tr2 = crashingdummy()

+                asyncore.readwrite(tr2, flag)

+                self.assertEqual(tr2.error_handled, True)

+

+            tobj = testobj()

+            self.assertEqual(tobj.write, False)

+            asyncore.readwrite(tobj, select.POLLOUT)

+            self.assertEqual(tobj.write, True)

+

+            # check that ExitNow exceptions in the object handler method

+            # bubbles all the way up through asyncore readwrite call

+            tr1 = exitingdummy()

+            self.assertRaises(asyncore.ExitNow, asyncore.readwrite, tr1,

+                              select.POLLOUT)

+

+            # check that an exception other than ExitNow in the object handler

+            # method causes the handle_error method to get called

+            tr2 = crashingdummy()

+            asyncore.readwrite(tr2, select.POLLOUT)

+            self.assertEqual(tr2.error_handled, True)

+

+            for flag in (select.POLLERR, select.POLLHUP, select.POLLNVAL):

+                tobj = testobj()

+                self.assertEqual(tobj.expt, False)

+                asyncore.readwrite(tobj, flag)

+                self.assertEqual(tobj.expt, True)

+

+                # check that ExitNow exceptions in the object handler method

+                # bubbles all the way up through asyncore readwrite calls

+                tr1 = exitingdummy()

+                self.assertRaises(asyncore.ExitNow, asyncore.readwrite, tr1, flag)

+

+                # check that an exception other than ExitNow in the object handler

+                # method causes the handle_error method to get called

+                tr2 = crashingdummy()

+                asyncore.readwrite(tr2, flag)

+                self.assertEqual(tr2.error_handled, True)

+

+    def test_closeall(self):

+        self.closeall_check(False)

+

+    def test_closeall_default(self):

+        self.closeall_check(True)

+

+    def closeall_check(self, usedefault):

+        # Check that close_all() closes everything in a given map

+

+        l = []

+        testmap = {}

+        for i in range(10):

+            c = dummychannel()

+            l.append(c)

+            self.assertEqual(c.socket.closed, False)

+            testmap[i] = c

+

+        if usedefault:

+            socketmap = asyncore.socket_map

+            try:

+                asyncore.socket_map = testmap

+                asyncore.close_all()

+            finally:

+                testmap, asyncore.socket_map = asyncore.socket_map, socketmap

+        else:

+            asyncore.close_all(testmap)

+

+        self.assertEqual(len(testmap), 0)

+

+        for c in l:

+            self.assertEqual(c.socket.closed, True)

+

+    def test_compact_traceback(self):

+        try:

+            raise Exception("I don't like spam!")

+        except:

+            real_t, real_v, real_tb = sys.exc_info()

+            r = asyncore.compact_traceback()

+        else:

+            self.fail("Expected exception")

+

+        (f, function, line), t, v, info = r

+        self.assertEqual(os.path.split(f)[-1], 'test_asyncore.py')

+        self.assertEqual(function, 'test_compact_traceback')

+        self.assertEqual(t, real_t)

+        self.assertEqual(v, real_v)

+        self.assertEqual(info, '[%s|%s|%s]' % (f, function, line))

+

+

+class DispatcherTests(unittest.TestCase):

+    def setUp(self):

+        pass

+

+    def tearDown(self):

+        asyncore.close_all()

+

+    def test_basic(self):

+        d = asyncore.dispatcher()

+        self.assertEqual(d.readable(), True)

+        self.assertEqual(d.writable(), True)

+

+    def test_repr(self):

+        d = asyncore.dispatcher()

+        self.assertEqual(repr(d), '<asyncore.dispatcher at %#x>' % id(d))

+

+    def test_log(self):

+        d = asyncore.dispatcher()

+

+        # capture output of dispatcher.log() (to stderr)

+        fp = StringIO()

+        stderr = sys.stderr

+        l1 = "Lovely spam! Wonderful spam!"

+        l2 = "I don't like spam!"

+        try:

+            sys.stderr = fp

+            d.log(l1)

+            d.log(l2)

+        finally:

+            sys.stderr = stderr

+

+        lines = fp.getvalue().splitlines()

+        self.assertEquals(lines, ['log: %s' % l1, 'log: %s' % l2])

+

+    def test_log_info(self):

+        d = asyncore.dispatcher()

+

+        # capture output of dispatcher.log_info() (to stdout via print)

+        fp = StringIO()

+        stdout = sys.stdout

+        l1 = "Have you got anything without spam?"

+        l2 = "Why can't she have egg bacon spam and sausage?"

+        l3 = "THAT'S got spam in it!"

+        try:

+            sys.stdout = fp

+            d.log_info(l1, 'EGGS')

+            d.log_info(l2)

+            d.log_info(l3, 'SPAM')

+        finally:

+            sys.stdout = stdout

+

+        lines = fp.getvalue().splitlines()

+        if __debug__:

+            expected = ['EGGS: %s' % l1, 'info: %s' % l2, 'SPAM: %s' % l3]

+        else:

+            expected = ['EGGS: %s' % l1, 'SPAM: %s' % l3]

+

+        self.assertEquals(lines, expected)

+

+    def test_unhandled(self):

+        d = asyncore.dispatcher()

+

+        # capture output of dispatcher.log_info() (to stdout via print)

+        fp = StringIO()

+        stdout = sys.stdout

+        try:

+            sys.stdout = fp

+            d.handle_expt()

+            d.handle_read()

+            d.handle_write()

+            d.handle_connect()

+            d.handle_accept()

+        finally:

+            sys.stdout = stdout

+

+        lines = fp.getvalue().splitlines()

+        expected = ['warning: unhandled exception',

+                    'warning: unhandled read event',

+                    'warning: unhandled write event',

+                    'warning: unhandled connect event',

+                    'warning: unhandled accept event']

+        self.assertEquals(lines, expected)

+

+

+

+class dispatcherwithsend_noread(asyncore.dispatcher_with_send):

+    def readable(self):

+        return False

+

+    def handle_connect(self):

+        pass

+

+class DispatcherWithSendTests(unittest.TestCase):

+    usepoll = False

+

+    def setUp(self):

+        pass

+

+    def tearDown(self):

+        asyncore.close_all()

+

+    def test_send(self):

+        self.evt = threading.Event()

+        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

+        self.sock.settimeout(3)

+        self.port = test_support.bind_port(self.sock)

+

+        cap = StringIO()

+        args = (self.evt, cap, self.sock)

+        threading.Thread(target=capture_server, args=args).start()

+

+        # wait a little longer for the server to initialize (it sometimes

+        # refuses connections on slow machines without this wait)

+        time.sleep(0.2)

+

+        data = "Suppose there isn't a 16-ton weight?"

+        d = dispatcherwithsend_noread()

+        d.create_socket(socket.AF_INET, socket.SOCK_STREAM)

+        d.connect((HOST, self.port))

+

+        # give time for socket to connect

+        time.sleep(0.1)

+

+        d.send(data)

+        d.send(data)

+        d.send('\n')

+

+        n = 1000

+        while d.out_buffer and n > 0:

+            asyncore.poll()

+            n -= 1

+

+        self.evt.wait()

+

+        self.assertEqual(cap.getvalue(), data*2)

+

+

+class DispatcherWithSendTests_UsePoll(DispatcherWithSendTests):

+    usepoll = True

+

+if hasattr(asyncore, 'file_wrapper'):

+    class FileWrapperTest(unittest.TestCase):

+        def setUp(self):

+            self.d = "It's not dead, it's sleeping!"

+            file(TESTFN, 'w').write(self.d)

+

+        def tearDown(self):

+            unlink(TESTFN)

+

+        def test_recv(self):

+            fd = os.open(TESTFN, os.O_RDONLY)

+            w = asyncore.file_wrapper(fd)

+

+            self.assertEqual(w.fd, fd)

+            self.assertEqual(w.fileno(), fd)

+            self.assertEqual(w.recv(13), "It's not dead")

+            self.assertEqual(w.read(6), ", it's")

+            w.close()

+            self.assertRaises(OSError, w.read, 1)

+

+        def test_send(self):

+            d1 = "Come again?"

+            d2 = "I want to buy some cheese."

+            fd = os.open(TESTFN, os.O_WRONLY | os.O_APPEND)

+            w = asyncore.file_wrapper(fd)

+

+            w.write(d1)

+            w.send(d2)

+            w.close()

+            self.assertEqual(file(TESTFN).read(), self.d + d1 + d2)

+

+

+def test_main():

+    tests = [HelperFunctionTests, DispatcherTests, DispatcherWithSendTests,

+             DispatcherWithSendTests_UsePoll]

+    if hasattr(asyncore, 'file_wrapper'):

+        tests.append(FileWrapperTest)

+

+    run_unittest(*tests)

+

+if __name__ == "__main__":

+    test_main()

diff --git a/Lib/test/test_ftplib.py b/Lib/test/test_ftplib.py
index 7c1f622..5f961d2 100644
--- a/Lib/test/test_ftplib.py
+++ b/Lib/test/test_ftplib.py
@@ -6,18 +6,13 @@ import time
 from unittest import TestCase
 from test import test_support
 
-server_port = None
+HOST = test_support.HOST
 
 # This function sets the evt 3 times:
 #  1) when the connection is ready to be accepted.
 #  2) when it is safe for the caller to close the connection
 #  3) when we have closed the socket
-def server(evt):
-    global server_port
-    serv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    serv.settimeout(3)
-    serv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-    server_port = test_support.bind_port(serv, "", 9091)
+def server(evt, serv):
     serv.listen(5)
     # (1) Signal the caller that we are ready to accept the connection.
     evt.set()
@@ -39,14 +34,16 @@ class GeneralTests(TestCase):
 
     def setUp(self):
         self.evt = threading.Event()
-        threading.Thread(target=server, args=(self.evt,)).start()
+        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.sock.settimeout(3)
+        self.port = test_support.bind_port(self.sock)
+        threading.Thread(target=server, args=(self.evt,self.sock)).start()
         # Wait for the server to be ready.
         self.evt.wait()
         self.evt.clear()
-        ftplib.FTP.port = server_port
+        ftplib.FTP.port = self.port
 
     def tearDown(self):
-        # Wait on the closing of the socket (this shouldn't be necessary).
         self.evt.wait()
 
     def testBasic(self):
@@ -54,34 +51,34 @@ class GeneralTests(TestCase):
         ftplib.FTP()
 
         # connects
-        ftp = ftplib.FTP("localhost")
+        ftp = ftplib.FTP(HOST)
         self.evt.wait()
         ftp.sock.close()
 
     def testTimeoutDefault(self):
         # default
-        ftp = ftplib.FTP("localhost")
+        ftp = ftplib.FTP(HOST)
         self.assertTrue(ftp.sock.gettimeout() is None)
         self.evt.wait()
         ftp.sock.close()
 
     def testTimeoutValue(self):
         # a value
-        ftp = ftplib.FTP("localhost", timeout=30)
+        ftp = ftplib.FTP(HOST, timeout=30)
         self.assertEqual(ftp.sock.gettimeout(), 30)
         self.evt.wait()
         ftp.sock.close()
 
     def testTimeoutConnect(self):
         ftp = ftplib.FTP()
-        ftp.connect("localhost", timeout=30)
+        ftp.connect(HOST, timeout=30)
         self.assertEqual(ftp.sock.gettimeout(), 30)
         self.evt.wait()
         ftp.sock.close()
 
     def testTimeoutDifferentOrder(self):
         ftp = ftplib.FTP(timeout=30)
-        ftp.connect("localhost")
+        ftp.connect(HOST)
         self.assertEqual(ftp.sock.gettimeout(), 30)
         self.evt.wait()
         ftp.sock.close()
@@ -89,7 +86,7 @@ class GeneralTests(TestCase):
     def testTimeoutDirectAccess(self):
         ftp = ftplib.FTP()
         ftp.timeout = 30
-        ftp.connect("localhost")
+        ftp.connect(HOST)
         self.assertEqual(ftp.sock.gettimeout(), 30)
         self.evt.wait()
         ftp.sock.close()
@@ -99,7 +96,7 @@ class GeneralTests(TestCase):
         previous = socket.getdefaulttimeout()
         socket.setdefaulttimeout(30)
         try:
-            ftp = ftplib.FTP("localhost", timeout=None)
+            ftp = ftplib.FTP(HOST, timeout=None)
         finally:
             socket.setdefaulttimeout(previous)
         self.assertEqual(ftp.sock.gettimeout(), 30)
diff --git a/Lib/test/test_httplib.py b/Lib/test/test_httplib.py
index 67719fd..68c0ac3 100644
--- a/Lib/test/test_httplib.py
+++ b/Lib/test/test_httplib.py
@@ -6,6 +6,8 @@ from unittest import TestCase
 
 from test import test_support
 
+HOST = test_support.HOST
+
 class FakeSocket:
     def __init__(self, text, fileclass=StringIO.StringIO):
         self.text = text
@@ -196,16 +198,12 @@ class OfflineTest(TestCase):
     def test_responses(self):
         self.assertEquals(httplib.responses[httplib.NOT_FOUND], "Not Found")
 
-PORT = 50003
-HOST = "localhost"
-
 class TimeoutTest(TestCase):
+    PORT = None
 
     def setUp(self):
         self.serv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        self.serv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-        global PORT
-        PORT = test_support.bind_port(self.serv, HOST, PORT)
+        self.PORT = test_support.bind_port(self.serv)
         self.serv.listen(5)
 
     def tearDown(self):
@@ -217,13 +215,13 @@ class TimeoutTest(TestCase):
         HTTPConnection and into the socket.
         '''
         # default
-        httpConn = httplib.HTTPConnection(HOST, PORT)
+        httpConn = httplib.HTTPConnection(HOST, self.PORT)
         httpConn.connect()
         self.assertTrue(httpConn.sock.gettimeout() is None)
         httpConn.close()
 
         # a value
-        httpConn = httplib.HTTPConnection(HOST, PORT, timeout=30)
+        httpConn = httplib.HTTPConnection(HOST, self.PORT, timeout=30)
         httpConn.connect()
         self.assertEqual(httpConn.sock.gettimeout(), 30)
         httpConn.close()
@@ -232,7 +230,7 @@ class TimeoutTest(TestCase):
         previous = socket.getdefaulttimeout()
         socket.setdefaulttimeout(30)
         try:
-            httpConn = httplib.HTTPConnection(HOST, PORT, timeout=None)
+            httpConn = httplib.HTTPConnection(HOST, self.PORT, timeout=None)
             httpConn.connect()
         finally:
             socket.setdefaulttimeout(previous)
@@ -246,11 +244,12 @@ class HTTPSTimeoutTest(TestCase):
     def test_attributes(self):
         # simple test to check it's storing it
         if hasattr(httplib, 'HTTPSConnection'):
-            h = httplib.HTTPSConnection(HOST, PORT, timeout=30)
+            h = httplib.HTTPSConnection(HOST, TimeoutTest.PORT, timeout=30)
             self.assertEqual(h.timeout, 30)
 
 def test_main(verbose=None):
-    test_support.run_unittest(HeaderTests, OfflineTest, BasicTest, TimeoutTest, HTTPSTimeoutTest)
+    test_support.run_unittest(HeaderTests, OfflineTest, BasicTest, TimeoutTest,
+                              HTTPSTimeoutTest)
 
 if __name__ == '__main__':
     test_main()
diff --git a/Lib/test/test_poplib.py b/Lib/test/test_poplib.py
index 35ff636..54b8786 100644
--- a/Lib/test/test_poplib.py
+++ b/Lib/test/test_poplib.py
@@ -6,12 +6,9 @@ import time
 from unittest import TestCase
 from test import test_support
 
+HOST = test_support.HOST
 
-def server(evt):
-    serv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    serv.settimeout(3)
-    serv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-    serv.bind(("", 9091))
+def server(evt, serv):
     serv.listen(5)
     try:
         conn, addr = serv.accept()
@@ -28,7 +25,10 @@ class GeneralTests(TestCase):
 
     def setUp(self):
         self.evt = threading.Event()
-        threading.Thread(target=server, args=(self.evt,)).start()
+        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.sock.settimeout(3)
+        self.port = test_support.bind_port(self.sock)
+        threading.Thread(target=server, args=(self.evt,self.sock)).start()
         time.sleep(.1)
 
     def tearDown(self):
@@ -36,18 +36,18 @@ class GeneralTests(TestCase):
 
     def testBasic(self):
         # connects
-        pop = poplib.POP3("localhost", 9091)
+        pop = poplib.POP3(HOST, self.port)
         pop.sock.close()
 
     def testTimeoutDefault(self):
         # default
-        pop = poplib.POP3("localhost", 9091)
+        pop = poplib.POP3(HOST, self.port)
         self.assertTrue(pop.sock.gettimeout() is None)
         pop.sock.close()
 
     def testTimeoutValue(self):
         # a value
-        pop = poplib.POP3("localhost", 9091, timeout=30)
+        pop = poplib.POP3(HOST, self.port, timeout=30)
         self.assertEqual(pop.sock.gettimeout(), 30)
         pop.sock.close()
 
@@ -56,7 +56,7 @@ class GeneralTests(TestCase):
         previous = socket.getdefaulttimeout()
         socket.setdefaulttimeout(30)
         try:
-            pop = poplib.POP3("localhost", 9091, timeout=None)
+            pop = poplib.POP3(HOST, self.port, timeout=None)
         finally:
             socket.setdefaulttimeout(previous)
         self.assertEqual(pop.sock.gettimeout(), 30)
diff --git a/Lib/test/test_smtplib.py b/Lib/test/test_smtplib.py
index 422933b..9e63110 100644
--- a/Lib/test/test_smtplib.py
+++ b/Lib/test/test_smtplib.py
@@ -12,18 +12,9 @@ import select
 from unittest import TestCase
 from test import test_support
 
-# PORT is used to communicate the port number assigned to the server
-# to the test client
-HOST = "localhost"
-PORT = None
-
-def server(evt, buf):
-    serv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    serv.settimeout(15)
-    serv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-    serv.bind(("", 0))
-    global PORT
-    PORT = serv.getsockname()[1]
+HOST = test_support.HOST
+
+def server(evt, buf, serv):
     serv.listen(5)
     evt.set()
     try:
@@ -43,14 +34,16 @@ def server(evt, buf):
         conn.close()
     finally:
         serv.close()
-        PORT = None
         evt.set()
 
 class GeneralTests(TestCase):
 
     def setUp(self):
         self.evt = threading.Event()
-        servargs = (self.evt, "220 Hola mundo\n")
+        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.sock.settimeout(15)
+        self.port = test_support.bind_port(self.sock)
+        servargs = (self.evt, "220 Hola mundo\n", self.sock)
         threading.Thread(target=server, args=servargs).start()
         self.evt.wait()
         self.evt.clear()
@@ -60,29 +53,29 @@ class GeneralTests(TestCase):
 
     def testBasic1(self):
         # connects
-        smtp = smtplib.SMTP(HOST, PORT)
+        smtp = smtplib.SMTP(HOST, self.port)
         smtp.sock.close()
 
     def testBasic2(self):
         # connects, include port in host name
-        smtp = smtplib.SMTP("%s:%s" % (HOST, PORT))
+        smtp = smtplib.SMTP("%s:%s" % (HOST, self.port))
         smtp.sock.close()
 
     def testLocalHostName(self):
         # check that supplied local_hostname is used
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname="testhost")
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname="testhost")
         self.assertEqual(smtp.local_hostname, "testhost")
         smtp.sock.close()
 
     def testTimeoutDefault(self):
         # default
-        smtp = smtplib.SMTP(HOST, PORT)
+        smtp = smtplib.SMTP(HOST, self.port)
         self.assertTrue(smtp.sock.gettimeout() is None)
         smtp.sock.close()
 
     def testTimeoutValue(self):
         # a value
-        smtp = smtplib.SMTP(HOST, PORT, timeout=30)
+        smtp = smtplib.SMTP(HOST, self.port, timeout=30)
         self.assertEqual(smtp.sock.gettimeout(), 30)
         smtp.sock.close()
 
@@ -91,7 +84,7 @@ class GeneralTests(TestCase):
         previous = socket.getdefaulttimeout()
         socket.setdefaulttimeout(30)
         try:
-            smtp = smtplib.SMTP(HOST, PORT, timeout=None)
+            smtp = smtplib.SMTP(HOST, self.port, timeout=None)
         finally:
             socket.setdefaulttimeout(previous)
         self.assertEqual(smtp.sock.gettimeout(), 30)
@@ -99,10 +92,7 @@ class GeneralTests(TestCase):
 
 
 # Test server thread using the specified SMTP server class
-def debugging_server(server_class, serv_evt, client_evt):
-    serv = server_class(("", 0), ('nowhere', -1))
-    global PORT
-    PORT = serv.getsockname()[1]
+def debugging_server(serv, serv_evt, client_evt):
     serv_evt.set()
 
     try:
@@ -131,7 +121,6 @@ def debugging_server(server_class, serv_evt, client_evt):
             time.sleep(0.5)
             serv.close()
         asyncore.close_all()
-        PORT = None
         serv_evt.set()
 
 MSG_BEGIN = '---------- MESSAGE FOLLOWS ----------\n'
@@ -153,7 +142,9 @@ class DebuggingServerTests(TestCase):
 
         self.serv_evt = threading.Event()
         self.client_evt = threading.Event()
-        serv_args = (smtpd.DebuggingServer, self.serv_evt, self.client_evt)
+        self.port = test_support.find_unused_port()
+        self.serv = smtpd.DebuggingServer((HOST, self.port), ('nowhere', -1))
+        serv_args = (self.serv, self.serv_evt, self.client_evt)
         threading.Thread(target=debugging_server, args=serv_args).start()
 
         # wait until server thread has assigned a port number
@@ -170,31 +161,31 @@ class DebuggingServerTests(TestCase):
 
     def testBasic(self):
         # connect
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=3)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=3)
         smtp.quit()
 
     def testNOOP(self):
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=3)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=3)
         expected = (250, 'Ok')
         self.assertEqual(smtp.noop(), expected)
         smtp.quit()
 
     def testRSET(self):
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=3)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=3)
         expected = (250, 'Ok')
         self.assertEqual(smtp.rset(), expected)
         smtp.quit()
 
     def testNotImplemented(self):
         # EHLO isn't implemented in DebuggingServer
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=3)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=3)
         expected = (502, 'Error: command "EHLO" not implemented')
         self.assertEqual(smtp.ehlo(), expected)
         smtp.quit()
 
     def testVRFY(self):
         # VRFY isn't implemented in DebuggingServer
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=3)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=3)
         expected = (502, 'Error: command "VRFY" not implemented')
         self.assertEqual(smtp.vrfy('nobody@nowhere.com'), expected)
         self.assertEqual(smtp.verify('nobody@nowhere.com'), expected)
@@ -203,21 +194,21 @@ class DebuggingServerTests(TestCase):
     def testSecondHELO(self):
         # check that a second HELO returns a message that it's a duplicate
         # (this behavior is specific to smtpd.SMTPChannel)
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=3)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=3)
         smtp.helo()
         expected = (503, 'Duplicate HELO/EHLO')
         self.assertEqual(smtp.helo(), expected)
         smtp.quit()
 
     def testHELP(self):
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=3)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=3)
         self.assertEqual(smtp.help(), 'Error: command "HELP" not implemented')
         smtp.quit()
 
     def testSend(self):
         # connect and send mail
         m = 'A test message'
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=3)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=3)
         smtp.sendmail('John', 'Sally', m)
         smtp.quit()
 
@@ -257,7 +248,10 @@ class BadHELOServerTests(TestCase):
         sys.stdout = self.output
 
         self.evt = threading.Event()
-        servargs = (self.evt, "199 no hello for you!\n")
+        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.sock.settimeout(15)
+        self.port = test_support.bind_port(self.sock)
+        servargs = (self.evt, "199 no hello for you!\n", self.sock)
         threading.Thread(target=server, args=servargs).start()
         self.evt.wait()
         self.evt.clear()
@@ -268,7 +262,7 @@ class BadHELOServerTests(TestCase):
 
     def testFailingHELO(self):
         self.assertRaises(smtplib.SMTPConnectError, smtplib.SMTP,
-                            HOST, PORT, 'localhost', 3)
+                            HOST, self.port, 'localhost', 3)
 
 
 sim_users = {'Mr.A@somewhere.com':'John A',
@@ -333,7 +327,9 @@ class SMTPSimTests(TestCase):
     def setUp(self):
         self.serv_evt = threading.Event()
         self.client_evt = threading.Event()
-        serv_args = (SimSMTPServer, self.serv_evt, self.client_evt)
+        self.port = test_support.find_unused_port()
+        self.serv = SimSMTPServer((HOST, self.port), ('nowhere', -1))
+        serv_args = (self.serv, self.serv_evt, self.client_evt)
         threading.Thread(target=debugging_server, args=serv_args).start()
 
         # wait until server thread has assigned a port number
@@ -348,11 +344,11 @@ class SMTPSimTests(TestCase):
 
     def testBasic(self):
         # smoke test
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=15)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=15)
         smtp.quit()
 
     def testEHLO(self):
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=15)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=15)
 
         # no features should be present before the EHLO
         self.assertEqual(smtp.esmtp_features, {})
@@ -373,7 +369,7 @@ class SMTPSimTests(TestCase):
         smtp.quit()
 
     def testVRFY(self):
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=15)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=15)
 
         for email, name in sim_users.items():
             expected_known = (250, '%s %s' % (name, smtplib.quoteaddr(email)))
@@ -385,7 +381,7 @@ class SMTPSimTests(TestCase):
         smtp.quit()
 
     def testEXPN(self):
-        smtp = smtplib.SMTP(HOST, PORT, local_hostname='localhost', timeout=15)
+        smtp = smtplib.SMTP(HOST, self.port, local_hostname='localhost', timeout=15)
 
         for listname, members in sim_lists.items():
             users = []
diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index 6140962..aaea042 100644
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -3,6 +3,7 @@
 import unittest
 from test import test_support
 
+import errno
 import socket
 import select
 import thread, threading
@@ -15,17 +16,14 @@ import array
 from weakref import proxy
 import signal
 
-PORT = 50007
-HOST = 'localhost'
+HOST = test_support.HOST
 MSG = 'Michael Gilfix was here\n'
 
 class SocketTCPTest(unittest.TestCase):
 
     def setUp(self):
         self.serv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        self.serv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-        global PORT
-        PORT = test_support.bind_port(self.serv, HOST, PORT)
+        self.port = test_support.bind_port(self.serv)
         self.serv.listen(1)
 
     def tearDown(self):
@@ -36,9 +34,7 @@ class SocketUDPTest(unittest.TestCase):
 
     def setUp(self):
         self.serv = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-        self.serv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-        global PORT
-        PORT = test_support.bind_port(self.serv, HOST, PORT)
+        self.port = test_support.bind_port(self.serv)
 
     def tearDown(self):
         self.serv.close()
@@ -185,7 +181,7 @@ class SocketConnectedTest(ThreadedTCPSocketTest):
 
     def clientSetUp(self):
         ThreadedTCPSocketTest.clientSetUp(self)
-        self.cli.connect((HOST, PORT))
+        self.cli.connect((HOST, self.port))
         self.serv_conn = self.cli
 
     def clientTearDown(self):
@@ -461,16 +457,23 @@ class GeneralModuleTests(unittest.TestCase):
     # XXX The following don't test module-level functionality...
 
     def testSockName(self):
-        # Testing getsockname()
+        # Testing getsockname().  Use a temporary socket to elicit an unused
+        # ephemeral port that we can use later in the test.
+        tempsock = socket.socket()
+        tempsock.bind(("0.0.0.0", 0))
+        (host, port) = tempsock.getsockname()
+        tempsock.close()
+        del tempsock
+
         sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        sock.bind(("0.0.0.0", PORT+1))
+        sock.bind(("0.0.0.0", port))
         name = sock.getsockname()
         # XXX(nnorwitz): http://tinyurl.com/os5jz seems to indicate
         # it reasonable to get the host's addr in addition to 0.0.0.0.
         # At least for eCos.  This is required for the S/390 to pass.
         my_ip_addr = socket.gethostbyname(socket.gethostname())
         self.assert_(name[0] in ("0.0.0.0", my_ip_addr), '%s invalid' % name[0])
-        self.assertEqual(name[1], PORT+1)
+        self.assertEqual(name[1], port)
 
     def testGetSockOpt(self):
         # Testing getsockopt()
@@ -597,7 +600,7 @@ class BasicUDPTest(ThreadedUDPSocketTest):
         self.assertEqual(msg, MSG)
 
     def _testSendtoAndRecv(self):
-        self.cli.sendto(MSG, 0, (HOST, PORT))
+        self.cli.sendto(MSG, 0, (HOST, self.port))
 
     def testRecvFrom(self):
         # Testing recvfrom() over UDP
@@ -605,14 +608,14 @@ class BasicUDPTest(ThreadedUDPSocketTest):
         self.assertEqual(msg, MSG)
 
     def _testRecvFrom(self):
-        self.cli.sendto(MSG, 0, (HOST, PORT))
+        self.cli.sendto(MSG, 0, (HOST, self.port))
 
     def testRecvFromNegative(self):
         # Negative lengths passed to recvfrom should give ValueError.
         self.assertRaises(ValueError, self.serv.recvfrom, -1)
 
     def _testRecvFromNegative(self):
-        self.cli.sendto(MSG, 0, (HOST, PORT))
+        self.cli.sendto(MSG, 0, (HOST, self.port))
 
 class TCPCloserTest(ThreadedTCPSocketTest):
 
@@ -626,7 +629,7 @@ class TCPCloserTest(ThreadedTCPSocketTest):
         self.assertEqual(sd.recv(1), '')
 
     def _testClose(self):
-        self.cli.connect((HOST, PORT))
+        self.cli.connect((HOST, self.port))
         time.sleep(1.0)
 
 class BasicSocketPairTest(SocketPairTest):
@@ -684,7 +687,7 @@ class NonBlockingTCPTests(ThreadedTCPSocketTest):
 
     def _testAccept(self):
         time.sleep(0.1)
-        self.cli.connect((HOST, PORT))
+        self.cli.connect((HOST, self.port))
 
     def testConnect(self):
         # Testing non-blocking connect
@@ -692,7 +695,7 @@ class NonBlockingTCPTests(ThreadedTCPSocketTest):
 
     def _testConnect(self):
         self.cli.settimeout(10)
-        self.cli.connect((HOST, PORT))
+        self.cli.connect((HOST, self.port))
 
     def testRecv(self):
         # Testing non-blocking recv
@@ -712,7 +715,7 @@ class NonBlockingTCPTests(ThreadedTCPSocketTest):
             self.fail("Error during select call to non-blocking socket.")
 
     def _testRecv(self):
-        self.cli.connect((HOST, PORT))
+        self.cli.connect((HOST, self.port))
         time.sleep(0.1)
         self.cli.send(MSG)
 
@@ -830,7 +833,9 @@ class SmallBufferedFileObjectClassTestCase(FileObjectClassTestCase):
 class NetworkConnectionTest(object):
     """Prove network connection."""
     def clientSetUp(self):
-        self.cli = socket.create_connection((HOST, PORT))
+        # We're inherited below by BasicTCPTest2, which also inherits
+        # BasicTCPTest, which defines self.port referenced below.
+        self.cli = socket.create_connection((HOST, self.port))
         self.serv_conn = self.cli
 
 class BasicTCPTest2(NetworkConnectionTest, BasicTCPTest):
@@ -839,7 +844,11 @@ class BasicTCPTest2(NetworkConnectionTest, BasicTCPTest):
 
 class NetworkConnectionNoServer(unittest.TestCase):
     def testWithoutServer(self):
-        self.failUnlessRaises(socket.error, lambda: socket.create_connection((HOST, PORT)))
+        port = test_support.find_unused_port()
+        self.failUnlessRaises(
+            socket.error,
+            lambda: socket.create_connection((HOST, port))
+        )
 
 class NetworkConnectionAttributesTest(SocketTCPTest, ThreadableTest):
 
@@ -860,22 +869,22 @@ class NetworkConnectionAttributesTest(SocketTCPTest, ThreadableTest):
 
     testFamily = _justAccept
     def _testFamily(self):
-        self.cli = socket.create_connection((HOST, PORT), timeout=30)
+        self.cli = socket.create_connection((HOST, self.port), timeout=30)
         self.assertEqual(self.cli.family, 2)
 
     testTimeoutDefault = _justAccept
     def _testTimeoutDefault(self):
-        self.cli = socket.create_connection((HOST, PORT))
+        self.cli = socket.create_connection((HOST, self.port))
         self.assertTrue(self.cli.gettimeout() is None)
 
     testTimeoutValueNamed = _justAccept
     def _testTimeoutValueNamed(self):
-        self.cli = socket.create_connection((HOST, PORT), timeout=30)
+        self.cli = socket.create_connection((HOST, self.port), timeout=30)
         self.assertEqual(self.cli.gettimeout(), 30)
 
     testTimeoutValueNonamed = _justAccept
     def _testTimeoutValueNonamed(self):
-        self.cli = socket.create_connection((HOST, PORT), 30)
+        self.cli = socket.create_connection((HOST, self.port), 30)
         self.assertEqual(self.cli.gettimeout(), 30)
 
     testTimeoutNone = _justAccept
@@ -883,7 +892,7 @@ class NetworkConnectionAttributesTest(SocketTCPTest, ThreadableTest):
         previous = socket.getdefaulttimeout()
         socket.setdefaulttimeout(30)
         try:
-            self.cli = socket.create_connection((HOST, PORT), timeout=None)
+            self.cli = socket.create_connection((HOST, self.port), timeout=None)
         finally:
             socket.setdefaulttimeout(previous)
         self.assertEqual(self.cli.gettimeout(), 30)
@@ -910,12 +919,12 @@ class NetworkConnectionBehaviourTest(SocketTCPTest, ThreadableTest):
     testOutsideTimeout = testInsideTimeout
 
     def _testInsideTimeout(self):
-        self.cli = sock = socket.create_connection((HOST, PORT))
+        self.cli = sock = socket.create_connection((HOST, self.port))
         data = sock.recv(5)
         self.assertEqual(data, "done!")
 
     def _testOutsideTimeout(self):
-        self.cli = sock = socket.create_connection((HOST, PORT), timeout=1)
+        self.cli = sock = socket.create_connection((HOST, self.port), timeout=1)
         self.failUnlessRaises(socket.timeout, lambda: sock.recv(5))
 
 
diff --git a/Lib/test/test_socket_ssl.py b/Lib/test/test_socket_ssl.py
index 266760f..5c49427 100644
--- a/Lib/test/test_socket_ssl.py
+++ b/Lib/test/test_socket_ssl.py
@@ -20,6 +20,7 @@ warnings.filterwarnings(
 # Optionally test SSL support, if we have it in the tested platform
 skip_expected = not hasattr(socket, "ssl")
 
+HOST = test_support.HOST
 
 class ConnectedTests(unittest.TestCase):
 
@@ -86,19 +87,16 @@ class ConnectedTests(unittest.TestCase):
 class BasicTests(unittest.TestCase):
 
     def testRudeShutdown(self):
-        # Some random port to connect to.
-        PORT = [9934]
-
         listener_ready = threading.Event()
         listener_gone = threading.Event()
-
-        # `listener` runs in a thread.  It opens a socket listening on
-        # PORT, and sits in an accept() until the main thread connects.
-        # Then it rudely closes the socket, and sets Event `listener_gone`
-        # to let the main thread know the socket is gone.
-        def listener():
-            s = socket.socket()
-            PORT[0] = test_support.bind_port(s, '', PORT[0])
+        sock = socket.socket()
+        port = test_support.bind_port(sock)
+
+        # `listener` runs in a thread.  It opens a socket and sits in accept()
+        # until the main thread connects.  Then it rudely closes the socket,
+        # and sets Event `listener_gone` to let the main thread know the socket
+        # is gone.
+        def listener(s):
             s.listen(5)
             listener_ready.set()
             s.accept()
@@ -108,7 +106,7 @@ class BasicTests(unittest.TestCase):
         def connector():
             listener_ready.wait()
             s = socket.socket()
-            s.connect(('localhost', PORT[0]))
+            s.connect((HOST, port))
             listener_gone.wait()
             try:
                 ssl_sock = socket.ssl(s)
@@ -118,7 +116,7 @@ class BasicTests(unittest.TestCase):
                 raise test_support.TestFailed(
                       'connecting to closed SSL socket should have failed')
 
-        t = threading.Thread(target=listener)
+        t = threading.Thread(target=listener, args=(sock,))
         t.start()
         connector()
         t.join()
@@ -169,7 +167,7 @@ class OpenSSLTests(unittest.TestCase):
 
     def testBasic(self):
         s = socket.socket()
-        s.connect(("localhost", 4433))
+        s.connect((HOST, OpenSSLServer.PORT))
         ss = socket.ssl(s)
         ss.write("Foo\n")
         i = ss.read(4)
@@ -183,7 +181,7 @@ class OpenSSLTests(unittest.TestCase):
         info = "/C=PT/ST=Queensland/L=Lisboa/O=Neuronio, Lda./OU=Desenvolvimento/CN=brutus.neuronio.pt/emailAddress=sampo@iki.fi"
 
         s = socket.socket()
-        s.connect(("localhost", 4433))
+        s.connect((HOST, OpenSSLServer.PORT))
         ss = socket.ssl(s)
         cert = ss.server()
         self.assertEqual(cert, info)
@@ -193,6 +191,7 @@ class OpenSSLTests(unittest.TestCase):
 
 
 class OpenSSLServer(threading.Thread):
+    PORT = None
     def __init__(self):
         self.s = None
         self.keepServing = True
@@ -211,7 +210,11 @@ class OpenSSLServer(threading.Thread):
             raise ValueError("No key file found! (tried %r)" % key_file)
 
         try:
-            cmd = "openssl s_server -cert %s -key %s -quiet" % (cert_file, key_file)
+            # XXX TODO: on Windows, this should make more effort to use the
+            # openssl.exe that would have been built by the pcbuild.sln.
+            self.PORT = test_support.find_unused_port()
+            args = (self.PORT, cert_file, key_file)
+            cmd = "openssl s_server -accept %d -cert %s -key %s -quiet" % args
             self.s = subprocess.Popen(cmd.split(), stdin=subprocess.PIPE,
                                        stdout=subprocess.PIPE,
                                        stderr=subprocess.STDOUT)
@@ -222,7 +225,7 @@ class OpenSSLServer(threading.Thread):
             # let's try if it is actually up
             try:
                 s = socket.socket()
-                s.connect(("localhost", 4433))
+                s.connect((HOST, self.PORT))
                 s.close()
                 if self.s.stdout.readline() != "ERROR\n":
                     raise ValueError
diff --git a/Lib/test/test_socketserver.py b/Lib/test/test_socketserver.py
index 457d231..8595e5a 100644
--- a/Lib/test/test_socketserver.py
+++ b/Lib/test/test_socketserver.py
@@ -22,7 +22,7 @@ from test.test_support import TESTFN as TEST_FILE
 test.test_support.requires("network")
 
 TEST_STR = "hello world\n"
-HOST = "localhost"
+HOST = test.test_support.HOST
 
 HAVE_UNIX_SOCKETS = hasattr(socket, "AF_UNIX")
 HAVE_FORKING = hasattr(os, "fork") and os.name != "os2"
diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py
index 8f8212a..eb4d00c 100644
--- a/Lib/test/test_ssl.py
+++ b/Lib/test/test_ssl.py
@@ -23,11 +23,10 @@ try:
 except ImportError:
     skip_expected = True
 
+HOST = test_support.HOST
 CERTFILE = None
 SVN_PYTHON_ORG_ROOT_CERT = None
 
-TESTPORT = 10025
-
 def handle_error(prefix):
     exc_format = ' '.join(traceback.format_exception(*sys.exc_info()))
     if test_support.verbose:
@@ -269,7 +268,7 @@ else:
                     except:
                         handle_error('')
 
-        def __init__(self, port, certificate, ssl_version=None,
+        def __init__(self, certificate, ssl_version=None,
                      certreqs=None, cacerts=None, expect_bad_connects=False,
                      chatty=True, connectionchatty=False, starttls_server=False):
             if ssl_version is None:
@@ -285,12 +284,8 @@ else:
             self.connectionchatty = connectionchatty
             self.starttls_server = starttls_server
             self.sock = socket.socket()
+            self.port = test_support.bind_port(self.sock)
             self.flag = None
-            if hasattr(socket, 'SO_REUSEADDR'):
-                self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-            if hasattr(socket, 'SO_REUSEPORT'):
-                self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
-            self.sock.bind(('127.0.0.1', port))
             self.active = False
             threading.Thread.__init__(self)
             self.setDaemon(False)
@@ -434,12 +429,13 @@ else:
                                       format%args))
 
 
-        def __init__(self, port, certfile):
+        def __init__(self, certfile):
             self.flag = None
             self.active = False
             self.RootedHTTPRequestHandler.root = os.path.split(CERTFILE)[0]
+            self.port = test_support.find_unused_port()
             self.server = self.HTTPSServer(
-                ('', port), self.RootedHTTPRequestHandler, certfile)
+                (HOST, self.port), self.RootedHTTPRequestHandler, certfile)
             threading.Thread.__init__(self)
             self.setDaemon(True)
 
@@ -465,7 +461,7 @@ else:
 
 
     def badCertTest (certfile):
-        server = ThreadedEchoServer(TESTPORT, CERTFILE,
+        server = ThreadedEchoServer(CERTFILE,
                                     certreqs=ssl.CERT_REQUIRED,
                                     cacerts=CERTFILE, chatty=False)
         flag = threading.Event()
@@ -478,7 +474,7 @@ else:
                 s = ssl.wrap_socket(socket.socket(),
                                     certfile=certfile,
                                     ssl_version=ssl.PROTOCOL_TLSv1)
-                s.connect(('127.0.0.1', TESTPORT))
+                s.connect((HOST, server.port))
             except ssl.SSLError, x:
                 if test_support.verbose:
                     sys.stdout.write("\nSSLError is %s\n" % x[1])
@@ -493,7 +489,7 @@ else:
                           client_certfile, client_protocol=None, indata="FOO\n",
                           chatty=True, connectionchatty=False):
 
-        server = ThreadedEchoServer(TESTPORT, certfile,
+        server = ThreadedEchoServer(certfile,
                                     certreqs=certreqs,
                                     ssl_version=protocol,
                                     cacerts=cacertsfile,
@@ -513,7 +509,7 @@ else:
                                     ca_certs=cacertsfile,
                                     cert_reqs=certreqs,
                                     ssl_version=client_protocol)
-                s.connect(('127.0.0.1', TESTPORT))
+                s.connect((HOST, server.port))
             except ssl.SSLError, x:
                 raise test_support.TestFailed("Unexpected SSL error:  " + str(x))
             except Exception, x:
@@ -582,6 +578,7 @@ else:
 
             listener_ready = threading.Event()
             listener_gone = threading.Event()
+            port = test_support.find_unused_port()
 
             # `listener` runs in a thread.  It opens a socket listening on
             # PORT, and sits in an accept() until the main thread connects.
@@ -589,11 +586,7 @@ else:
             # to let the main thread know the socket is gone.
             def listener():
                 s = socket.socket()
-                if hasattr(socket, 'SO_REUSEADDR'):
-                    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-                if hasattr(socket, 'SO_REUSEPORT'):
-                    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
-                s.bind(('127.0.0.1', TESTPORT))
+                s.bind((HOST, port))
                 s.listen(5)
                 listener_ready.set()
                 s.accept()
@@ -603,7 +596,7 @@ else:
             def connector():
                 listener_ready.wait()
                 s = socket.socket()
-                s.connect(('127.0.0.1', TESTPORT))
+                s.connect((HOST, port))
                 listener_gone.wait()
                 try:
                     ssl_sock = ssl.wrap_socket(s)
@@ -631,7 +624,7 @@ else:
             if test_support.verbose:
                 sys.stdout.write("\n")
             s2 = socket.socket()
-            server = ThreadedEchoServer(TESTPORT, CERTFILE,
+            server = ThreadedEchoServer(CERTFILE,
                                         certreqs=ssl.CERT_NONE,
                                         ssl_version=ssl.PROTOCOL_SSLv23,
                                         cacerts=CERTFILE,
@@ -648,7 +641,7 @@ else:
                                         ca_certs=CERTFILE,
                                         cert_reqs=ssl.CERT_REQUIRED,
                                         ssl_version=ssl.PROTOCOL_SSLv23)
-                    s.connect(('127.0.0.1', TESTPORT))
+                    s.connect((HOST, server.port))
                 except ssl.SSLError, x:
                     raise test_support.TestFailed(
                         "Unexpected SSL error:  " + str(x))
@@ -748,7 +741,7 @@ else:
 
             msgs = ("msg 1", "MSG 2", "STARTTLS", "MSG 3", "msg 4")
 
-            server = ThreadedEchoServer(TESTPORT, CERTFILE,
+            server = ThreadedEchoServer(CERTFILE,
                                         ssl_version=ssl.PROTOCOL_TLSv1,
                                         starttls_server=True,
                                         chatty=True,
@@ -763,7 +756,7 @@ else:
                 try:
                     s = socket.socket()
                     s.setblocking(1)
-                    s.connect(('127.0.0.1', TESTPORT))
+                    s.connect((HOST, server.port))
                 except Exception, x:
                     raise test_support.TestFailed("Unexpected exception:  " + str(x))
                 else:
@@ -805,7 +798,7 @@ else:
 
         def testAsyncore(self):
 
-            server = AsyncoreHTTPSServer(TESTPORT, CERTFILE)
+            server = AsyncoreHTTPSServer(CERTFILE)
             flag = threading.Event()
             server.start(flag)
             # wait for it to start
@@ -817,8 +810,8 @@ else:
                 d1 = open(CERTFILE, 'rb').read()
                 d2 = ''
                 # now fetch the same data from the HTTPS server
-                url = 'https://127.0.0.1:%d/%s' % (
-                    TESTPORT, os.path.split(CERTFILE)[1])
+                url = 'https://%s:%d/%s' % (
+                    HOST, server.port, os.path.split(CERTFILE)[1])
                 f = urllib.urlopen(url)
                 dlen = f.info().getheader("content-length")
                 if dlen and (int(dlen) > 0):
@@ -842,29 +835,11 @@ else:
                 server.join()
 
 
-def findtestsocket(start, end):
-    def testbind(i):
-        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        try:
-            s.bind(("127.0.0.1", i))
-        except:
-            return 0
-        else:
-            return 1
-        finally:
-            s.close()
-
-    for i in range(start, end):
-        if testbind(i) and testbind(i+1):
-            return i
-    return 0
-
-
 def test_main(verbose=False):
     if skip_expected:
         raise test_support.TestSkipped("No SSL support")
 
-    global CERTFILE, TESTPORT, SVN_PYTHON_ORG_ROOT_CERT
+    global CERTFILE, SVN_PYTHON_ORG_ROOT_CERT
     CERTFILE = os.path.join(os.path.dirname(__file__) or os.curdir,
                             "keycert.pem")
     SVN_PYTHON_ORG_ROOT_CERT = os.path.join(
@@ -874,9 +849,6 @@ def test_main(verbose=False):
     if (not os.path.exists(CERTFILE) or
         not os.path.exists(SVN_PYTHON_ORG_ROOT_CERT)):
         raise test_support.TestFailed("Can't read certificate files!")
-    TESTPORT = findtestsocket(10025, 12000)
-    if not TESTPORT:
-        raise test_support.TestFailed("Can't find open port to test servers on!")
 
     tests = [BasicTests]
 
diff --git a/Lib/test/test_support.py b/Lib/test/test_support.py
index 7a5f30a..2a9474e 100644
--- a/Lib/test/test_support.py
+++ b/Lib/test/test_support.py
@@ -103,31 +103,97 @@ def requires(resource, msg=None):
             msg = "Use of the `%s' resource not enabled" % resource
         raise ResourceDenied(msg)
 
-def bind_port(sock, host='', preferred_port=54321):
-    """Try to bind the sock to a port.  If we are running multiple
-    tests and we don't try multiple ports, the test can fail.  This
-    makes the test more robust."""
-
-    # Find some random ports that hopefully no one is listening on.
-    # Ideally each test would clean up after itself and not continue listening
-    # on any ports.  However, this isn't the case.  The last port (0) is
-    # a stop-gap that asks the O/S to assign a port.  Whenever the warning
-    # message below is printed, the test that is listening on the port should
-    # be fixed to close the socket at the end of the test.
-    # Another reason why we can't use a port is another process (possibly
-    # another instance of the test suite) is using the same port.
-    for port in [preferred_port, 9907, 10243, 32999, 0]:
-        try:
-            sock.bind((host, port))
-            if port == 0:
-                port = sock.getsockname()[1]
-            return port
-        except socket.error, (err, msg):
-            if err != errno.EADDRINUSE:
-                raise
-            print >>sys.__stderr__, \
-                '  WARNING: failed to listen on port %d, trying another' % port
-    raise TestFailed('unable to find port to listen on')
+HOST = 'localhost'
+
+def find_unused_port(family=socket.AF_INET, socktype=socket.SOCK_STREAM):
+    """Returns an unused port that should be suitable for binding.  This is
+    achieved by creating a temporary socket with the same family and type as
+    the 'sock' parameter (default is AF_INET, SOCK_STREAM), and binding it to
+    the specified host address (defaults to 0.0.0.0) with the port set to 0,
+    eliciting an unused ephemeral port from the OS.  The temporary socket is
+    then closed and deleted, and the ephemeral port is returned.
+
+    Either this method or bind_port() should be used for any tests where a
+    server socket needs to be bound to a particular port for the duration of
+    the test.  Which one to use depends on whether the calling code is creating
+    a python socket, or if an unused port needs to be provided in a constructor
+    or passed to an external program (i.e. the -accept argument to openssl's
+    s_server mode).  Always prefer bind_port() over find_unused_port() where
+    possible.  Hard coded ports should *NEVER* be used.  As soon as a server
+    socket is bound to a hard coded port, the ability to run multiple instances
+    of the test simultaneously on the same host is compromised, which makes the
+    test a ticking time bomb in a buildbot environment. On Unix buildbots, this
+    may simply manifest as a failed test, which can be recovered from without
+    intervention in most cases, but on Windows, the entire python process can
+    completely and utterly wedge, requiring someone to log in to the buildbot
+    and manually kill the affected process.
+
+    (This is easy to reproduce on Windows, unfortunately, and can be traced to
+    the SO_REUSEADDR socket option having different semantics on Windows versus
+    Unix/Linux.  On Unix, you can't have two AF_INET SOCK_STREAM sockets bind,
+    listen and then accept connections on identical host/ports.  An EADDRINUSE
+    socket.error will be raised at some point (depending on the platform and
+    the order bind and listen were called on each socket).
+
+    However, on Windows, if SO_REUSEADDR is set on the sockets, no EADDRINUSE
+    will ever be raised when attempting to bind two identical host/ports. When
+    accept() is called on each socket, the second caller's process will steal
+    the port from the first caller, leaving them both in an awkwardly wedged
+    state where they'll no longer respond to any signals or graceful kills, and
+    must be forcibly killed via OpenProcess()/TerminateProcess().
+
+    The solution on Windows is to use the SO_EXCLUSIVEADDRUSE socket option
+    instead of SO_REUSEADDR, which effectively affords the same semantics as
+    SO_REUSEADDR on Unix.  Given the propensity of Unix developers in the Open
+    Source world compared to Windows ones, this is a common mistake.  A quick
+    look over OpenSSL's 0.9.8g source shows that they use SO_REUSEADDR when
+    openssl.exe is called with the 's_server' option, for example. See
+    http://bugs.python.org/issue2550 for more info.  The following site also
+    has a very thorough description about the implications of both REUSEADDR
+    and EXCLUSIVEADDRUSE on Windows:
+    http://msdn2.microsoft.com/en-us/library/ms740621(VS.85).aspx)
+
+    XXX: although this approach is a vast improvement on previous attempts to
+    elicit unused ports, it rests heavily on the assumption that the ephemeral
+    port returned to us by the OS won't immediately be dished back out to some
+    other process when we close and delete our temporary socket but before our
+    calling code has a chance to bind the returned port.  We can deal with this
+    issue if/when we come across it."""
+    tempsock = socket.socket(family, socktype)
+    port = bind_port(tempsock)
+    tempsock.close()
+    del tempsock
+    return port
+
+def bind_port(sock, host=HOST):
+    """Bind the socket to a free port and return the port number.  Relies on
+    ephemeral ports in order to ensure we are using an unbound port.  This is
+    important as many tests may be running simultaneously, especially in a
+    buildbot environment.  This method raises an exception if the sock.family
+    is AF_INET and sock.type is SOCK_STREAM, *and* the socket has SO_REUSEADDR
+    or SO_REUSEPORT set on it.  Tests should *never* set these socket options
+    for TCP/IP sockets.  The only case for setting these options is testing
+    multicasting via multiple UDP sockets.
+
+    Additionally, if the SO_EXCLUSIVEADDRUSE socket option is available (i.e.
+    on Windows), it will be set on the socket.  This will prevent anyone else
+    from bind()'ing to our host/port for the duration of the test.
+    """
+    if sock.family == socket.AF_INET and sock.type == socket.SOCK_STREAM:
+        if hasattr(socket, 'SO_REUSEADDR'):
+            if sock.getsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR) == 1:
+                raise TestFailed("tests should never set the SO_REUSEADDR "   \
+                                 "socket option on TCP/IP sockets!")
+        if hasattr(socket, 'SO_REUSEPORT'):
+            if sock.getsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT) == 1:
+                raise TestFailed("tests should never set the SO_REUSEPORT "   \
+                                 "socket option on TCP/IP sockets!")
+        if hasattr(socket, 'SO_EXCLUSIVEADDRUSE'):
+            sock.setsockopt(socket.SOL_SOCKET, socket.SO_EXCLUSIVEADDRUSE, 1)
+
+    sock.bind((host, 0))
+    port = sock.getsockname()[1]
+    return port
 
 FUZZ = 1e-6
 
diff --git a/Lib/test/test_telnetlib.py b/Lib/test/test_telnetlib.py
index 8eee666..e4ee1b5 100644
--- a/Lib/test/test_telnetlib.py
+++ b/Lib/test/test_telnetlib.py
@@ -6,14 +6,9 @@ import time
 from unittest import TestCase
 from test import test_support
 
-PORT = 9091
+HOST = test_support.HOST
 
-def server(evt):
-    serv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    serv.settimeout(3)
-    serv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-    global PORT
-    PORT = test_support.bind_port(serv, "", PORT)
+def server(evt, serv):
     serv.listen(5)
     evt.set()
     try:
@@ -28,7 +23,10 @@ class GeneralTests(TestCase):
 
     def setUp(self):
         self.evt = threading.Event()
-        threading.Thread(target=server, args=(self.evt,)).start()
+        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.sock.settimeout(3)
+        self.port = test_support.bind_port(self.sock)
+        threading.Thread(target=server, args=(self.evt,self.sock)).start()
         self.evt.wait()
         self.evt.clear()
         time.sleep(.1)
@@ -38,24 +36,24 @@ class GeneralTests(TestCase):
 
     def testBasic(self):
         # connects
-        telnet = telnetlib.Telnet("localhost", PORT)
+        telnet = telnetlib.Telnet(HOST, self.port)
         telnet.sock.close()
 
     def testTimeoutDefault(self):
         # default
-        telnet = telnetlib.Telnet("localhost", PORT)
+        telnet = telnetlib.Telnet(HOST, self.port)
         self.assertTrue(telnet.sock.gettimeout() is None)
         telnet.sock.close()
 
     def testTimeoutValue(self):
         # a value
-        telnet = telnetlib.Telnet("localhost", PORT, timeout=30)
+        telnet = telnetlib.Telnet(HOST, self.port, timeout=30)
         self.assertEqual(telnet.sock.gettimeout(), 30)
         telnet.sock.close()
 
     def testTimeoutDifferentOrder(self):
         telnet = telnetlib.Telnet(timeout=30)
-        telnet.open("localhost", PORT)
+        telnet.open(HOST, self.port)
         self.assertEqual(telnet.sock.gettimeout(), 30)
         telnet.sock.close()
 
@@ -64,7 +62,7 @@ class GeneralTests(TestCase):
         previous = socket.getdefaulttimeout()
         socket.setdefaulttimeout(30)
         try:
-            telnet = telnetlib.Telnet("localhost", PORT, timeout=None)
+            telnet = telnetlib.Telnet(HOST, self.port, timeout=None)
         finally:
             socket.setdefaulttimeout(previous)
         self.assertEqual(telnet.sock.gettimeout(), 30)
diff --git a/Misc/NEWS b/Misc/NEWS
index 747267b..1c086c3 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -41,6 +41,43 @@ Library
 
 Tests
 -----
+- Issue #2550: The approach used by client/server code for obtaining ports
+  to listen on in network-oriented tests has been refined in an effort to
+  facilitate running multiple instances of the entire regression test suite
+  in parallel without issue.  test_support.bind_port() has been fixed such
+  that it will always return a unique port -- which wasn't always the case
+  with the previous implementation, especially if socket options had been
+  set that affected address reuse (i.e. SO_REUSEADDR, SO_REUSEPORT).  The
+  new implementation of bind_port() will actually raise an exception if it
+  is passed an AF_INET/SOCK_STREAM socket with either the SO_REUSEADDR or 
+  SO_REUSEPORT socket option set.  Furthermore, if available, bind_port()
+  will set the SO_EXCLUSIVEADDRUSE option on the socket it's been passed.
+  This currently only applies to Windows.  This option prevents any other
+  sockets from binding to the host/port we've bound to, thus removing the
+  possibility of the 'non-deterministic' behaviour, as Microsoft puts it,
+  that occurs when a second SOCK_STREAM socket binds and accepts to a 
+  host/port that's already been bound by another socket.  The optional 
+  preferred port parameter to bind_port() has been removed.  Under no
+  circumstances should tests be hard coding ports!
+  
+  test_support.find_unused_port() has also been introduced, which will pass
+  a temporary socket object to bind_port() in order to obtain an unused port.
+  The temporary socket object is then closed and deleted, and the port is
+  returned.  This method should only be used for obtaining an unused port
+  in order to pass to an external program (i.e. the -accept [port] argument
+  to openssl's s_server mode) or as a parameter to a server-oriented class
+  that doesn't give you direct access to the underlying socket used.
+
+  Finally, test_support.HOST has been introduced, which should be used for
+  the host argument of any relevant socket calls (i.e. bind and connect).
+
+  The following tests were updated to following the new conventions:
+    test_socket, test_smtplib, test_asyncore, test_ssl, test_httplib, 
+    test_poplib, test_ftplib, test_telnetlib, test_socketserver,
+    test_asynchat and test_socket_ssl.
+
+  It is now possible for multiple instances of the regression test suite to
+  run in parallel without issue.
 
 Build
 -----