Test failures with Python 3.11

[sergiopasra]

Description

I'm building astropy 5.1 with a prerelease of python 3.11 for the next Fedora release. I'm getting this error in the tests:

=================================== FAILURES ===================================
_______ test_simple_object[0-StaticMatrixTransform-args6-kwargs6-False] ________
pickle_protocol = 0
name = <class 'astropy.coordinates.transformations.StaticMatrixTransform'>
args = [array([[1., 0., 0.],
       [0., 1., 0.],
       [0., 0., 1.]]), <class 'astropy.coordinates.builtin_frames.icrs.ICRS'>, <class 'astropy.coordinates.builtin_frames.icrs.ICRS'>]
kwargs = {}, xfail = False
    @pytest.mark.parametrize(("name", "args", "kwargs", "xfail"),
                             zip(_names, _args, _kwargs, _xfail))
    def test_simple_object(pickle_protocol, name, args, kwargs, xfail):
        # Tests easily instantiated objects
        if xfail:
            pytest.xfail()
        original = name(*args, **kwargs)
>       check_pickling_recovery(original, pickle_protocol)
astropy/coordinates/tests/test_pickle.py:71: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
astropy/tests/helper.py:446: in check_pickling_recovery
    generic_recursive_equality_test(original, unpickled,
astropy/tests/helper.py:433: in generic_recursive_equality_test
    generic_recursive_equality_test(dict_a[key],
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
a = <class 'astropy.coordinates.builtin_frames.icrs.ICRS'>
b = <class 'astropy.coordinates.builtin_frames.icrs.ICRS'>
class_history = [<class 'abc.ABCMeta'>, <class 'astropy.coordinates.transformations.StaticMatrixTransform'>]
    def generic_recursive_equality_test(a, b, class_history):
        """
        Check if the attributes of a and b are equal. Then,
        check if the attributes of the attributes are equal.
        """
>       dict_a = a.__getstate__() if hasattr(a, '__getstate__') else a.__dict__
E       TypeError: unbound method object.__getstate__() needs an argument
astropy/tests/helper.py:415: TypeError

This is probably related with a change in how objects are pickled. Now object has a default implementation of `getstate

https://docs.python.org/3.11/library/pickle.html#object.__getstate__

Full details in the Fedora bug report: https://bugzilla.redhat.com/show_bug.cgi?id=2101963

[pllim]

Hello! Do you mean astropy 5.1? There is no 5.10 release. Also, did you try with the dev version? I vaguely remember some fix to the pickling in dev not too long ago.

We have no yet tested astropy against Python 3.11. @astropy/devops-maintainers , should we do it now?

[sergiopasra]

Hello! Do you mean astropy 5.1? There is no 5.10 release. Also, did you try with the dev version? I vaguely remember some fix to the pickling in dev not too long ago.

Yes, 5.1

I have tried the tests in b6352e1 and it has the same errors in:

coordinates/tests/test_pickle.py::test_simple_object[0-StaticMatrixTransform-args6-kwargs6-False]
coordinates/tests/test_pickle.py::test_simple_object[1-StaticMatrixTransform-args6-kwargs6-False]
coordinates/tests/test_pickle.py::test_simple_object[-1-StaticMatrixTransform-args6-kwargs6-False]

[sergiopasra]

The following tests fail also with python 3.11 (both with devel and 5.1)

astropy/coordinates/tests/test_pickle.py::test_simple_object
astropy/cosmology/flrw/tests/test_base.py::TestFLRW::test_name
astropy/cosmology/flrw/tests/test_lambdacdm.py::TestLambdaCDM::test_name
astropy/cosmology/flrw/tests/test_lambdacdm.py::TestFlatLambdaCDM::test_name
astropy/cosmology/flrw/tests/test_w0cdm.py::TestwCDM::test_name
astropy/cosmology/flrw/tests/test_w0cdm.py::TestFlatwCDM::test_name
astropy/cosmology/flrw/tests/test_w0wacdm.py::Testw0waCDM::test_name
astropy/cosmology/flrw/tests/test_w0wacdm.py::TestFlatw0waCDM::test_name
astropy/cosmology/flrw/tests/test_w0wzcdm.py::Testw0wzCDM::test_name
astropy/cosmology/flrw/tests/test_wpwazpcdm.py::TestwpwaCDM::test_name
astropy/cosmology/tests/test_core.py::TestCosmology::test_name
astropy/table/tests/test_pprint.py::TestColumnsShowHide::test_remove[pprint_exclude_names]
astropy/table/tests/test_pprint.py::TestColumnsShowHide::test_remove[pprint_include_names]
astropy/time/tests/test_mask.py::test_mask_not_writeable

[pllim]

Hmm lots of cosmology in there... @nstarman ?

Though ultimately, this is hard to fix until we update CI to test against Python 3.11. Maybe soon... I just noticed RC1 is out. https://docs.python.org/3.11/whatsnew/3.11.html

[nstarman]

I'll be happy to squash these bugs, just as soon as there's a conda python 3.11 version available, (even a release candidate) :)

[pllim]

See the failure log in #13614 . Thanks!

[pllim]

@sergiopasra , please try again with latest dev astropy. Should be fixed now. Thanks for your patience!