Hi, Martin. I replied your last comment and your patch looks good to me except one test fails:

[1/1] test_zlib
test_abcdefghijklmnop (test.test_zlib.ChecksumTestCase)
test issue1202 compliance: signed crc32, adler32 in 2.x ... ok
test_adler32empty (test.test_zlib.ChecksumTestCase) ... ok
test_adler32start (test.test_zlib.ChecksumTestCase) ... ok
test_crc32empty (test.test_zlib.ChecksumTestCase) ... ok
test_crc32start (test.test_zlib.ChecksumTestCase) ... ok
test_negative_crc_iv_input (test.test_zlib.ChecksumTestCase) ... ok
test_penguins (test.test_zlib.ChecksumTestCase) ... ok
test_same_as_binascii_crc32 (test.test_zlib.ChecksumTestCase) ... ok
test_big_buffer (test.test_zlib.ChecksumBigBufferTestCase) ... ERROR
test_badcompressobj (test.test_zlib.ExceptionTestCase) ... ok
test_baddecompressobj (test.test_zlib.ExceptionTestCase) ... ok
test_badlevel (test.test_zlib.ExceptionTestCase) ... ok
test_decompressobj_badflush (test.test_zlib.ExceptionTestCase) ... ok
test_overflow (test.test_zlib.ExceptionTestCase) ... ok
test_64bit_compress (test.test_zlib.CompressTestCase) ... ok
test_big_compress_buffer (test.test_zlib.CompressTestCase) ... ok
test_big_decompress_buffer (test.test_zlib.CompressTestCase) ... ok
test_custom_bufsize (test.test_zlib.CompressTestCase) ... ok
test_incomplete_stream (test.test_zlib.CompressTestCase) ... ok
test_large_bufsize (test.test_zlib.CompressTestCase) ... ok
test_speech (test.test_zlib.CompressTestCase) ... ok
test_speech128 (test.test_zlib.CompressTestCase) ... ok
test_64bit_compress (test.test_zlib.CompressObjectTestCase) ... ok
test_badcompresscopy (test.test_zlib.CompressObjectTestCase) ... ok
test_baddecompresscopy (test.test_zlib.CompressObjectTestCase) ... ok
test_big_compress_buffer (test.test_zlib.CompressObjectTestCase) ... ok
test_big_decompress_buffer (test.test_zlib.CompressObjectTestCase) ... ok
test_clear_unconsumed_tail (test.test_zlib.CompressObjectTestCase) ... ok
test_compresscopy (test.test_zlib.CompressObjectTestCase) ... ok
test_compressincremental (test.test_zlib.CompressObjectTestCase) ... ok
test_compressoptions (test.test_zlib.CompressObjectTestCase) ... ok
test_compresspickle (test.test_zlib.CompressObjectTestCase) ... ok
test_decompimax (test.test_zlib.CompressObjectTestCase) ... ok
test_decompinc (test.test_zlib.CompressObjectTestCase) ... ok
test_decompincflush (test.test_zlib.CompressObjectTestCase) ... ok
test_decompress_incomplete_stream (test.test_zlib.CompressObjectTestCase) ... ok
test_decompress_unused_data (test.test_zlib.CompressObjectTestCase) ... ok
test_decompresscopy (test.test_zlib.CompressObjectTestCase) ... ok
test_decompressmaxlen (test.test_zlib.CompressObjectTestCase) ... ok
test_decompressmaxlenflush (test.test_zlib.CompressObjectTestCase) ... ok
test_decompresspickle (test.test_zlib.CompressObjectTestCase) ... ok
test_empty_flush (test.test_zlib.CompressObjectTestCase) ... ok
test_flush_custom_length (test.test_zlib.CompressObjectTestCase) ... ok
test_flush_large_length (test.test_zlib.CompressObjectTestCase) ... ok
test_flush_with_freed_input (test.test_zlib.CompressObjectTestCase) ... ok
test_flushes (test.test_zlib.CompressObjectTestCase) ... ok
test_large_unconsumed_tail (test.test_zlib.CompressObjectTestCase) ... ok
test_large_unused_data (test.test_zlib.CompressObjectTestCase) ... ok
test_maxlen_custom (test.test_zlib.CompressObjectTestCase) ... ok
test_maxlen_large (test.test_zlib.CompressObjectTestCase) ... ok
test_maxlenmisc (test.test_zlib.CompressObjectTestCase) ... ok
test_odd_flush (test.test_zlib.CompressObjectTestCase) ... ok
test_pair (test.test_zlib.CompressObjectTestCase) ... ok
test_wbits (test.test_zlib.CompressObjectTestCase) ... ok

======================================================================
ERROR: test_big_buffer (test.test_zlib.ChecksumBigBufferTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/home/zhangxiang3/Python-2.7.12/Lib/test/test_support.py", line 1348, in wrapper
    return f(self, maxsize)
  File "/usr/home/zhangxiang3/Python-2.7.12/Lib/test/test_zlib.py", line 90, in test_big_buffer
    ChecksumTestCase.assertEqual32(self, zlib.crc32(data), 1044521549)
TypeError: unbound method assertEqual32() must be called with ChecksumTestCase instance as first argument (got ChecksumBigBufferTestCase instance instead)

----------------------------------------------------------------------
Ran 54 tests in 317.008s

FAILED (errors=1)
test test_zlib failed -- Traceback (most recent call last):
  File "/usr/home/zhangxiang3/Python-2.7.12/Lib/test/test_support.py", line 1348, in wrapper
    return f(self, maxsize)
  File "/usr/home/zhangxiang3/Python-2.7.12/Lib/test/test_zlib.py", line 90, in test_big_buffer
    ChecksumTestCase.assertEqual32(self, zlib.crc32(data), 1044521549)
TypeError: unbound method assertEqual32() must be called with ChecksumTestCase instance as first argument (got ChecksumBigBufferTestCase instance instead)

1 test failed:
    test_zlib