Don't block unix sockets

pytest_socket.py

@@ -34,6 +34,12 @@ def pytest_addoption(parser):
         metavar='ALLOWED_HOSTS_CSV',
         help='Only allow specified hosts through socket.socket.connect((host, port)).'
     )
+    group.addoption(
+        '--allow-unix-socket',
+        action='store_true',
+        dest='allow_unix_socket',
+        help='Allow calls if they are to Unix domain sockets'
+    )
 
 
 @pytest.fixture(autouse=True)
@@ -55,28 +61,39 @@ def _socket_marker(request):
 
 
 @pytest.fixture
-def socket_disabled():
+def socket_disabled(pytestconfig):
     """ disable socket.socket for duration of this test function """
-    disable_socket()
+    allow_unix_socket = pytestconfig.getoption('--allow-unix-socket')
+    disable_socket(allow_unix_socket)
     yield
     enable_socket()
 
 
 @pytest.fixture
-def socket_enabled():
+def socket_enabled(pytestconfig):
     """ enable socket.socket for duration of this test function """
     enable_socket()
     yield
-    disable_socket()
+    allow_unix_socket = pytestconfig.getoption('--allow-unix-socket')
+    disable_socket(allow_unix_socket)
 
 
-def disable_socket():
+def disable_socket(allow_unix_socket=False):
     """ disable socket.socket to disable the Internet. useful in testing.
     """
 
     class GuardedSocket(socket.socket):
         """ socket guard to disable socket creation (from pytest-socket) """
         def __new__(cls, *args, **kwargs):
+            try:
+                is_unix_socket = args[0] == socket.AF_UNIX
+            except AttributeError:
+                # AF_UNIX not supported on Windows https://bugs.python.org/issue33408
+                is_unix_socket = False
+
+            if is_unix_socket and allow_unix_socket:
+                return super().__new__(cls, *args, **kwargs)
+
             raise SocketBlockedError()
 
     socket.socket = GuardedSocket

tests/test_socket.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 import pytest
+import socket
 
 from pytest_socket import enable_socket
 
@@ -228,3 +229,29 @@ class MySocket(socket.socket):
     """)
     result = testdir.runpytest("--verbose")
     assert_socket_blocked(result)
+
+
+@pytest.mark.skipif(not hasattr(socket, "AF_UNIX"), reason="Skip any platform that does not support AF_UNIX")
+def test_unix_domain_sockets_blocked_with_disable_socket(testdir):
+    testdir.makepyfile("""
+        import socket
+
+        def test_unix_socket():
+            socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    """)
+    result = testdir.runpytest("--verbose", "--disable-socket")
+    assert_socket_blocked(result)
+
+
+@pytest.mark.skipif(not hasattr(socket, "AF_UNIX"), reason="Skip any platform that does not support AF_UNIX")
+def test_enabling_unix_domain_sockets_with_disable_socket(testdir):
+    testdir.makepyfile("""
+        import socket
+
+        def test_inet():
+            socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        def test_unix_socket():
+            socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    """)
+    result = testdir.runpytest("--verbose", "--disable-socket", "--allow-unix-socket")
+    result.assert_outcomes(passed=1, skipped=0, failed=1)