Issue 28668: Merge 3.5

Lib/test/support/__init__.py

@@ -90,7 +90,7 @@ __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_android_level",
+    "check__all__", "requires_android_level", "requires_multiprocessing_queue",
     # sys
     "is_jython", "is_android", "check_impl_detail", "unix_shell",
     # network
@@ -1752,6 +1752,22 @@ 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: