diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index f1fb615..c98117a 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -523,7 +523,7 @@
         len_typeobject = p + 2*l + 15*p + l + 4*p + l + 9*p +\
                          l + 11*p + self.align(4)
         self.check_sizeof(class_newstyle,
-                          h + len_typeobject + 41*p + 10*p + 3*p + 6*p)
+                          h + len_typeobject + 42*p + 10*p + 3*p + 6*p)
 
     def test_specialtypes(self):
         i = self.i