Add a test to make sure zlib.crc32 and binascii.crc32 return the same thing.

Fix a buglet in binascii.crc32, the second optional argument could previously
have a signedness mismatch with the C variable its going into.

Lib/test/test_zlib.py

 import unittest
 from test import test_support
 import zlib
+import binascii
 import random
 
 
@@ -47,6 +48,11 @@ class ChecksumTestCase(unittest.TestCase):
         self.assertEqual(zlib.adler32(foo+foo), -721416943)
         self.assertEqual(zlib.adler32('spam'), 72286642)
 
+    def test_same_as_binascii_crc32(self):
+        foo = 'abcdefghijklmnop'
+        self.assertEqual(binascii.crc32(foo), zlib.crc32(foo))
+        self.assertEqual(binascii.crc32('spam'), zlib.crc32('spam'))
+
 
 
 class ExceptionTestCase(unittest.TestCase):

Modules/binascii.c

@@ -874,7 +874,7 @@ binascii_crc32(PyObject *self, PyObject *args)
 	Py_ssize_t len;
 	long result;
 
-	if ( !PyArg_ParseTuple(args, "s#|l:crc32", &bin_data, &len, &crc) )
+	if ( !PyArg_ParseTuple(args, "s#|k:crc32", &bin_data, &len, &crc) )
 		return NULL;
 
 	crc = ~ crc;