diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py

index 0dd4258..d9b3267 100644

--- a/Lib/test/test_sys.py

+++ b/Lib/test/test_sys.py

@@ -769,6 +769,11 @@ class SizeofTest(unittest.TestCase):

                   '10P'                 # PySequenceMethods

                   '6P'                  # PyBufferProcs

                   '2P')

+

+        # COUNT_ALLOCS adds further fields to the end of a PyTypeObject:

+        if hasattr(sys, 'getcounts'):

+            s += size('P')

+

         class newstyleclass(object):

             pass

         check(newstyleclass, s)