Skip multiprocessing using tests when run from py.test on Windows

test/test_util.py

@@ -11,10 +11,14 @@
 import multiprocessing
 import subprocess
 import traceback
+import pytest
 
 from asv import util
 
 
+WIN = (os.name == 'nt')
+
+
 def _multiprocessing_raise_processerror(arg):
     try:
         raise util.ProcessError(["a"], 1, "aa", "bb")
@@ -34,6 +38,11 @@ def _multiprocessing_raise_usererror(arg):
 def test_parallelfailure():
     # Check the workaround for https://bugs.python.org/issue9400 works
 
+    if WIN and os.path.basename(sys.argv[0]).lower().startswith('py.test'):
+        # Multiprocessing in spawn mode can result to problems with py.test
+        pytest.skip("Multiprocessing spawn mode on Windows not safe to run "
+                    "from py.test runner.")
+
     # The exception class must be pickleable
     exc = util.ParallelFailure("test", Exception, "something")
     exc2 = pickle.loads(pickle.dumps(exc))