Test failures with Python 3.12 b1 & b2

[hrnciar]

Hello,

I'd like to ask for help with tornado and its compatibility with Python 3.12. Up until the 7th alpha tornado was building fine. I started to see the following failures with the 1st beta. You can see the failure also in CI of this PR #3277.

Thank you.

======================================================================
FAIL: test_chunked (tornado.test.httpclient_test.HTTPClientCommonTestCase.test_chunked)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/testing.py", line 102, in __call__
    result = self.orig_method(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/test/httpclient_test.py", line 225, in test_chunked
    self.assertEqual(chunks, [b"asdf", b"qwer"])
AssertionError: Lists differ: [b'asdfqwer'] != [b'asdf', b'qwer']

First differing element 0:
b'asdfqwer'
b'asdf'

Second list contains 1 additional elements.
First extra element 1:
b'qwer'

- [b'asdfqwer']
+ [b'asdf', b'qwer']
?        +++++


======================================================================
FAIL: test_gzip (tornado.test.httpclient_test.HTTPClientCommonTestCase.test_gzip)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/testing.py", line 102, in __call__
    result = self.orig_method(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/test/httpclient_test.py", line 438, in test_gzip
    self.assertEqual(len(response.body), 34)
AssertionError: 28 != 34

======================================================================
FAIL: test_header_callback (tornado.test.httpclient_test.HTTPClientCommonTestCase.test_header_callback)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/testing.py", line 102, in __call__
    result = self.orig_method(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/test/httpclient_test.py", line 484, in test_header_callback
    self.assertEqual(chunks, [b"asdf", b"qwer"])
AssertionError: Lists differ: [b'asdfqwer'] != [b'asdf', b'qwer']

First differing element 0:
b'asdfqwer'
b'asdf'

Second list contains 1 additional elements.
First extra element 1:
b'qwer'

- [b'asdfqwer']
+ [b'asdf', b'qwer']
?        +++++


======================================================================
FAIL: test_chunked (tornado.test.simple_httpclient_test.SimpleHTTPClientCommonTestCase.test_chunked)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/testing.py", line 102, in __call__
    result = self.orig_method(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/test/httpclient_test.py", line 225, in test_chunked
    self.assertEqual(chunks, [b"asdf", b"qwer"])
AssertionError: Lists differ: [b'asdfqwer'] != [b'asdf', b'qwer']

First differing element 0:
b'asdfqwer'
b'asdf'

Second list contains 1 additional elements.
First extra element 1:
b'qwer'

- [b'asdfqwer']
+ [b'asdf', b'qwer']
?        +++++


======================================================================
FAIL: test_gzip (tornado.test.simple_httpclient_test.SimpleHTTPClientCommonTestCase.test_gzip)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/testing.py", line 102, in __call__
    result = self.orig_method(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/test/httpclient_test.py", line 438, in test_gzip
    self.assertEqual(len(response.body), 34)
AssertionError: 28 != 34

======================================================================
FAIL: test_header_callback (tornado.test.simple_httpclient_test.SimpleHTTPClientCommonTestCase.test_header_callback)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/testing.py", line 102, in __call__
    result = self.orig_method(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/builddir/build/BUILD/tornado-6.3.2/tornado/test/httpclient_test.py", line 484, in test_header_callback
    self.assertEqual(chunks, [b"asdf", b"qwer"])
AssertionError: Lists differ: [b'asdfqwer'] != [b'asdf', b'qwer']

First differing element 0:
b'asdfqwer'
b'asdf'

Second list contains 1 additional elements.
First extra element 1:
b'qwer'

- [b'asdfqwer']
+ [b'asdf', b'qwer']
?        +++++


----------------------------------------------------------------------
Ran 1189 tests in 17.011s

FAILED (failures=6, skipped=66)

[bdarnell]

This is a bug introduced by a change to the python standard library's gzip module: python/cpython#105808. Hopefully it'll get fixed in an upcoming beta.

There are also other things that broke with the 3.12 betas: we need to upgrade tox, and there are some deprecation warnings in datetime that we have to work around. I have patches for those issues but there's no clean way to work around the GzipFile bug so I'm going to disable 3.12 in CI until the fix comes out.