bpo-28668: test.support.requires_multiprocessing_queue is removed (GH-4560)

Skip tests with test.support.import_module('multiprocessing.synchronize')
instead when the semaphore implementation is broken or missing.

Lib/test/support/__init__.py

@@ -87,8 +87,7 @@ __all__ = [
     "bigmemtest", "bigaddrspacetest", "cpython_only", "get_attribute",
     "requires_IEEE_754", "skip_unless_xattr", "requires_zlib",
     "anticipate_failure", "load_package_tests", "detect_api_mismatch",
-    "check__all__", "requires_multiprocessing_queue",
-    "skip_unless_bind_unix_socket",
+    "check__all__", "skip_unless_bind_unix_socket",
     # sys
     "is_jython", "is_android", "check_impl_detail", "unix_shell",
     "setswitchinterval",
@@ -1791,22 +1790,6 @@ def impl_detail(msg=None, **guards):
         msg = msg.format(' or '.join(guardnames))
     return unittest.skip(msg)
 
-_have_mp_queue = None
-def requires_multiprocessing_queue(test):
-    """Skip decorator for tests that use multiprocessing.Queue."""
-    global _have_mp_queue
-    if _have_mp_queue is None:
-        import multiprocessing
-        # Without a functioning shared semaphore implementation attempts to
-        # instantiate a Queue will result in an ImportError (issue #3770).
-        try:
-            multiprocessing.Queue()
-            _have_mp_queue = True
-        except ImportError:
-            _have_mp_queue = False
-    msg = "requires a functioning shared semaphore implementation"
-    return test if _have_mp_queue else unittest.skip(msg)(test)
-
 def _parse_guards(guards):
     # Returns a tuple ({platform_name: run_me}, default_value)
     if not guards:

Lib/test/test_logging.py

@@ -3211,9 +3211,11 @@ if hasattr(logging.handlers, 'QueueListener'):
             self.assertEqual(mock_handle.call_count, 5 * self.repeat,
                              'correct number of handled log messages')
 
-        @support.requires_multiprocessing_queue
         @patch.object(logging.handlers.QueueListener, 'handle')
         def test_handle_called_with_mp_queue(self, mock_handle):
+            # Issue 28668: The multiprocessing (mp) module is not functional
+            # when the mp.synchronize module cannot be imported.
+            support.import_module('multiprocessing.synchronize')
             for i in range(self.repeat):
                 log_queue = multiprocessing.Queue()
                 self.setup_and_log(log_queue, '%s_%s' % (self.id(), i))
@@ -3230,7 +3232,6 @@ if hasattr(logging.handlers, 'QueueListener'):
             except queue.Empty:
                 return []
 
-        @support.requires_multiprocessing_queue
         def test_no_messages_in_queue_after_stop(self):
             """
             Five messages are logged then the QueueListener is stopped. This
@@ -3238,6 +3239,9 @@ if hasattr(logging.handlers, 'QueueListener'):
             indicates that messages were not registered on the queue until
             _after_ the QueueListener stopped.
             """
+            # Issue 28668: The multiprocessing (mp) module is not functional
+            # when the mp.synchronize module cannot be imported.
+            support.import_module('multiprocessing.synchronize')
             for i in range(self.repeat):
                 queue = multiprocessing.Queue()
                 self.setup_and_log(queue, '%s_%s' %(self.id(), i))

Misc/NEWS.d/next/Tests/2017-11-25-14-53-29.bpo-28668.Y1G6pA.rst

@@ -0,0 +1,3 @@
+test.support.requires_multiprocessing_queue is removed. Skip tests with
+test.support.import_module('multiprocessing.synchronize') instead when the
+semaphore implementation is broken or missing.