test_bio_membuf: Use fork when running on MacOS

Restores Python pre-3.8 multiprocessing start method when running
test_readline() under MacOS.

Fixes #286

1 files changed, 20 insertions, 1 deletions

diff --git a/tests/test_bio_membuf.py b/tests/test_bio_membuf.py
index 16e9c03..6fe5120 100644
--- a/tests/test_bio_membuf.py
+++ b/tests/test_bio_membuf.py
@@ -7,6 +7,9 @@ Copyright (c) 2000 Ng Pheng Siong. All rights reserved."""
 import os
 import multiprocessing
 
+from platform import system
+from sys import version_info
+from M2Crypto import six
 from M2Crypto.BIO import MemoryBuffer
 from tests import unittest
 
@@ -16,7 +19,23 @@ class TimeLimitExpired(Exception):
 
 
 def time_limit(timeout, func, exc_msg, *args, **kwargs):
-    p = multiprocessing.Process(target=func)
+
+    # multiprocessing.get_context() available in Python >= 3.4
+    if six.PY3:
+        # Python >=3.8 on MacOS changed start_method to 'spawn' as default.
+        #   This creates a new context with the previous 'fork'
+        #   start_method. Fixes issue #286.
+        if system() == 'Darwin' and version_info.major >= 3 and version_info.minor >= 8:
+            start_method = 'fork'
+        else:
+            # use default context
+            start_method = None
+
+        mp = multiprocessing.get_context(start_method)
+    else:
+        mp = multiprocessing
+
+    p = mp.Process(target=func)
     p.start()
     p.join(timeout)
     if p.is_alive():