Test failures with Python 3.15.0b1: test_bad_payload_exception[zlib] and test_loads_unsafe[zlib] #420

$ uv venv -p 3.15
Using CPython 3.15.0b1 interpreter at: /usr/bin/python3.15
Creating virtual environment at: .venv
Activate with: source .venv/bin/activate
$ uv pip install -e . --group=tests
Resolved 9 packages in 2ms
      Built itsdangerous @ file:///tmp/itsdangerous
Prepared 1 package in 164ms
░░░░░░░░░░░░░░░░░░░░ [0/9] Installing wheels...                                                                                        warning: Failed to hardlink files; falling back to full copy. This may lead to degraded performance.
         If the cache and target directories are on different filesystems, hardlinking may not be supported.
         If this is intentional, set `export UV_LINK_MODE=copy` or use `--link-mode=copy` to suppress this warning.
Installed 9 packages in 15ms
 + freezegun==1.5.5
 + iniconfig==2.3.0
 + itsdangerous==2.3.0.dev0 (from file:///tmp/itsdangerous)
 + packaging==26.2
 + pluggy==1.6.0
 + pygments==2.20.0
 + pytest==9.0.3
 + python-dateutil==2.9.0.post0
 + six==1.17.0
$ .venv/bin/pytest
========================================================= test session starts =========================================================
platform linux -- Python 3.15.0b1, pytest-9.0.3, pluggy-1.6.0
rootdir: /tmp/itsdangerous
configfile: pyproject.toml
testpaths: tests
collected 297 items                                                                                                                   

tests/test_itsdangerous/test_encoding.py ........                                                                               [  2%]
tests/test_itsdangerous/test_serializer.py .........................................                                            [ 16%]
tests/test_itsdangerous/test_signer.py .................                                                                        [ 22%]
tests/test_itsdangerous/test_timed.py ......................................................................................... [ 52%]
............                                                                                                                    [ 56%]
tests/test_itsdangerous/test_url_safe.py ...................................................................................... [ 85%]
.........................F.F................                                                                                    [100%]

============================================================== FAILURES ===============================================================
_____________________________________ TestURLSafeTimedSerializer.test_bad_payload_exception[zlib] _____________________________________

self = <test_itsdangerous.test_url_safe.TestURLSafeTimedSerializer object at 0x7f30bde13650>
serializer = <itsdangerous.url_safe.URLSafeTimedSerializer object at 0x7f30bd735860>
value = 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'

    def test_bad_payload_exception(self, serializer: Serializer, value: Any):
        original = serializer.dumps(value)
        payload = original.rsplit(coerce_str(original, "."), 1)[0]  # type: ignore
        bad = serializer.make_signer().sign(payload[:-1])
    
>       with pytest.raises(BadPayload) as exc_info:
             ^^^^^^^^^^^^^^^^^^^^^^^^^
E       Failed: DID NOT RAISE <class 'itsdangerous.exc.BadPayload'>

tests/test_itsdangerous/test_serializer.py:85: Failed
_________________________________________ TestURLSafeTimedSerializer.test_loads_unsafe[zlib] __________________________________________

self = <test_itsdangerous.test_url_safe.TestURLSafeTimedSerializer object at 0x7f30bde183d0>
serializer = <itsdangerous.url_safe.URLSafeTimedSerializer object at 0x7f30bd730af0>
value = 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'

    def test_loads_unsafe(self, serializer: Serializer, value: Any):
        signed = serializer.dumps(value)
        assert serializer.loads_unsafe(signed) == (True, value)
    
        bad_signed = signed[:-1]
        assert serializer.loads_unsafe(bad_signed) == (False, value)
    
        payload = signed.rsplit(coerce_str(signed, "."), 1)[0]  # type: ignore
        bad_payload = serializer.make_signer().sign(payload[:-1])[:-1]
>       assert serializer.loads_unsafe(bad_payload) == (False, None)
E       AssertionError: assert (False, 'aaaa...aaaaaaaaaaaa') == (False, None)
E         
E         At index 1 diff: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...
E         
E         ...Full output truncated (2 lines hidden), use '-vv' to show

tests/test_itsdangerous/test_serializer.py:99: AssertionError
======================================================= short test summary info =======================================================
FAILED tests/test_itsdangerous/test_url_safe.py::TestURLSafeTimedSerializer::test_bad_payload_exception[zlib] - Failed: DID NOT RAISE <class 'itsdangerous.exc.BadPayload'>
FAILED tests/test_itsdangerous/test_url_safe.py::TestURLSafeTimedSerializer::test_loads_unsafe[zlib] - AssertionError: assert (False, 'aaaa...aaaaaaaaaaaa') == (False, None)
==================================================== 2 failed, 295 passed in 0.85s ====================================================