--- a/Lib/test/support.py	Sun Jul 29 20:30:36 2012 +1000
+++ b/Lib/test/support.py	Sun Jul 29 16:38:45 2012 +0200
@@ -25,6 +25,7 @@
 import logging.handlers
 import struct
 import tempfile
+import _testcapi
 
 try:
     import _thread, threading
@@ -1082,6 +1083,33 @@
     return final_opt != '' and final_opt != '-O0'
 
 
+_header = 'nP'
+_align = '0n'
+if hasattr(sys, "gettotalrefcount"):
+    _header = '2P' + _header
+    _align = '0P'
+_vheader = _header + 'n'
+
+def calcobjsize(fmt):
+    return struct.calcsize(_header + fmt + _align)
+
+def calcvobjsize(fmt):
+    return struct.calcsize(_vheader + fmt + _align)
+
+
+_TPFLAGS_HAVE_GC = 1<<14
+_TPFLAGS_HEAPTYPE = 1<<9
+
+def check_sizeof(test, o, size):
+    result = sys.getsizeof(o)
+    # add GC header size
+    if ((type(o) == type) and (o.__flags__ & _TPFLAGS_HEAPTYPE) or\
+        ((type(o) != type) and (type(o).__flags__ & _TPFLAGS_HAVE_GC))):
+        size += _testcapi.SIZEOF_PYGC_HEAD
+    msg = 'wrong size for %s: got %d, expected %d' \
+            % (type(o), result, size)
+    test.assertEqual(result, size, msg)
+
 #=======================================================================
 # Decorator for running a function in a different locale, correctly resetting
 # it afterwards.