[Python-Dev] [Python-checkins] cpython (2.7): Issue #10276: test_zlib checks that inputs of 2 GB are handled correctly by (original) (raw)

Victor Stinner victor.stinner at haypocalc.com
Tue May 3 22:38:43 CEST 2011

Le mardi 03 mai 2011 à 16:22 +0200, Nadeem Vawda a écrit :

On Tue, May 3, 2011 at 3:19 PM, victor.stinner <python-checkins at python.org> wrote: > +# Issue #10276 - check that inputs of 2 GB are handled correctly. > +# Be aware of issues #1202, #8650, #8651 and #10276 > +class ChecksumBigBufferTestCase(unittest.TestCase): > + intmax = 0x7FFFFFFF > + > + @unittest.skipUnless(mmap, "mmap() is not available.") > + def testbigbuffer(self): > + if sys.platform[:3] == 'win' or sys.platform == 'darwin': > + requires('largefile', > + 'test requires %s bytes and a long time to run' % > + str(self.intmax)) > + try: > + with open(TESTFN, "wb+") as f: > + f.seek(self.intmax-4) > + f.write("asdf") > + f.flush() > + try: > + m = mmap.mmap(f.fileno(), 0, access=mmap.ACCESSREAD) > + self.assertEqual(zlib.crc32(m), 0x709418e7) > + self.assertEqual(zlib.adler32(m), -2072837729) > + finally: > + m.close() > + except (IOError, OverflowError): > + raise unittest.SkipTest("filesystem doesn't have largefile support") > + finally: > + unlink(TESTFN) > + > +

0x7FFFFFFF is (2G-1) bytes. For a 2GB buffer, intmax should be 0x80000000. However, if you make this change, crc32() and adler32() raise OverflowErrors (see changeset a0681e7a6ded).

I don't want to check OverflowError: the test is supposed to compute the checksum of a buffer of 0x7FFFFFFF bytes, to check crc32() and adler32(). 0x7FFFFFFF is the biggest size supported by these functions (zlib doesn't use Py_ssize_t in Python 2.7).

If you use a buffer of 0x80000000 bytes, you test PyArg_Parse*() functions, which have already a dedicated test (in test_xml_etree_c, it's not the best file to store such test...).

Also, the assignment to m needs to be moved outside of the inner try...finally block.

Yeah, I noticed this with buildbots: already fixed by dd58f8072216.

As an aside, in this sort of situation is it better to just go and commit a fix myself, or is raising it on the mailing list first the right way to do things?

I'm not sure that you understood the test, so I think that it's better to ask first on IRC and/or the mailing list.

Victor

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