- 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.

1 files changed, 37 insertions, 28 deletions

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))