gh-91960: Add FreeBSD build and test using Cirrus-CI [DEBUG PR]

.cirrus.yml

@@ -0,0 +1,14 @@
+freebsd_task:
+  freebsd_instance:
+    matrix:
+    - image: freebsd-13-2-release-amd64
+  build_script:
+    - mkdir build
+    - cd build
+    - ../configure
+    - make -j$(sysctl -n hw.ncpu)
+    - make pythoninfo
+  test_script:
+    - cd build
+    # dtrace fails to build on FreeBSD - see gh-73263
+    - make buildbottest TESTOPTS="-j0 -u-network -x test_dtrace"

Lib/test/support/socket_helper.py

@@ -3,6 +3,7 @@
 import os.path
 import socket
 import sys
+import subprocess
 import tempfile
 import unittest
 
@@ -277,3 +278,52 @@ def create_unix_domain_name():
     """
     return tempfile.mktemp(prefix="test_python_", suffix='.sock',
                            dir=os.path.curdir)
+
+
+# consider that sysctl values should not change while tests are running
+_sysctl_cache = {}
+
+def _get_sysctl(name):
+    """Get a sysctl value as an integer."""
+    try:
+        return _sysctl_cache[name]
+    except KeyError:
+        pass
+
+    cmd = ['sysctl', name]
+    proc = subprocess.run(cmd,
+                          stdout=subprocess.PIPE,
+                          stderr=subprocess.STDOUT,
+                          text=True)
+    if proc.returncode:
+        return None
+    # Parse 'net.inet.tcp.blackhole: 0\n' to get '0'
+    value = proc.stdout.rstrip().split(': ')[-1]
+    try:
+        value = int(value)
+    except ValueError:
+        return None
+
+    _sysctl_cache[name] = value
+    return value
+
+
+def tcp_blackhole():
+    if not sys.platform.startswith('freebsd'):
+        return False
+
+    # gh-91960: test if FreeBSD TCP blackhost is enabled
+    value = _get_sysctl('net.inet.tcp.blackhole')
+    if value is None:
+        # don't skip if we fail to get the sysctl value
+        return False
+    return (value != 0)
+
+
+def skip_if_tcp_blackhole(test):
+    """Decorator for tests requiring a functional bind() for unix sockets."""
+    skip_if = unittest.skipIf(
+        tcp_blackhole(),
+        "TCP blackhost is enabled (sysctl net.inet.tcp.blackhole)"
+    )
+    return skip_if(test)

Lib/test/test_asyncio/test_events.py

@@ -1271,6 +1271,7 @@ def connection_made(self, transport):
 
         server.close()
 
+    @socket_helper.skip_if_tcp_blackhole
     def test_server_close(self):
         f = self.loop.create_server(MyProto, '0.0.0.0', 0)
         server = self.loop.run_until_complete(f)

Lib/test/test_asyncio/test_sock_lowlevel.py

@@ -10,6 +10,11 @@
 from test import support
 from test.support import socket_helper
 
+if socket_helper.tcp_blackhole():
+    raise unittest.SkipTest('Not relevant to ProactorEventLoop')
+
+
+
 def tearDownModule():
     asyncio.set_event_loop_policy(None)
 

Lib/test/test_asyncio/test_sslproto.py

@@ -5,6 +5,7 @@
 import unittest
 import weakref
 from test import support
+from test.support import socket_helper
 from unittest import mock
 try:
     import ssl
@@ -350,6 +351,7 @@ async def client(addr):
         support.gc_collect()
         self.assertIsNone(client_context())
 
+    @socket_helper.skip_if_tcp_blackhole
     def test_start_tls_client_buf_proto_1(self):
         HELLO_MSG = b'1' * self.PAYLOAD_SIZE
 
@@ -502,6 +504,7 @@ async def client(addr):
                 asyncio.wait_for(client(srv.addr),
                                  timeout=support.SHORT_TIMEOUT))
 
+    @socket_helper.skip_if_tcp_blackhole
     def test_start_tls_server_1(self):
         HELLO_MSG = b'1' * self.PAYLOAD_SIZE
         ANSWER = b'answer'

Lib/test/test_imaplib.py

@@ -74,6 +74,7 @@ def test_that_Time2Internaldate_returns_a_result(self):
         for t in self.timevalues():
             imaplib.Time2Internaldate(t)
 
+    @socket_helper.skip_if_tcp_blackhole
     def test_imap4_host_default_value(self):
         # Check whether the IMAP4_PORT is truly unavailable.
         with socket.socket() as s:

Lib/test/test_socket.py

@@ -5288,6 +5288,7 @@ def mocked_socket_module(self):
         finally:
             socket.socket = old_socket
 
+    @socket_helper.skip_if_tcp_blackhole
     def test_connect(self):
         port = socket_helper.find_unused_port()
         cli = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
@@ -5296,6 +5297,7 @@ def test_connect(self):
             cli.connect((HOST, port))
         self.assertEqual(cm.exception.errno, errno.ECONNREFUSED)
 
+    @socket_helper.skip_if_tcp_blackhole
     def test_create_connection(self):
         # Issue #9792: errors raised by create_connection() should have
         # a proper errno attribute.

Misc/NEWS.d/next/Tests/2023-09-05-21-42-54.gh-issue-91960.abClTs.rst

@@ -0,0 +1 @@
+FreeBSD 13.2 CI coverage for pull requests is now provided by Cirrus-CI (a hosted CI service that supports Linux, macOS, Windows, and FreeBSD).