Test failure on Python 3.12 due to datetime.datetime.utcnow() deprecation

[musicinmybrain]

tox -e py312

================================================= FAILURES =================================================
_________________ DescribeCorePropertiesPart.it_can_create_a_default_core_properties_part __________________

self = <tests.opc.parts.test_coreprops.DescribeCorePropertiesPart object at 0x7f50c936b6e0>

    def it_can_create_a_default_core_properties_part(self):
>       core_properties_part = CorePropertiesPart.default(None)

tests/opc/parts/test_coreprops.py:22: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

cls = <class 'docx.opc.parts.coreprops.CorePropertiesPart'>, package = None

    @classmethod
    def default(cls, package):
        """Return a new |CorePropertiesPart| object initialized with default values for
        its base properties."""
        core_properties_part = cls._new(package)
        core_properties = core_properties_part.core_properties
        core_properties.title = "Word Document"
        core_properties.last_modified_by = "python-docx"
        core_properties.revision = 1
>       core_properties.modified = datetime.utcnow()
E       DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.now(datetime.UTC).

.tox/py312/lib/python3.12/site-packages/docx/opc/parts/coreprops.py:25: DeprecationWarning
========================================= short test summary info ==========================================
FAILED tests/opc/parts/test_coreprops.py::DescribeCorePropertiesPart::it_can_create_a_default_core_properties_part - DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future vers...
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! stopping after 1 failures !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1 failed, 676 passed in 3.44s
py312: exit 1 (3.66 seconds) /home/ben/src/forks/python-docx> py.test -qx pid=1743764
.pkg: _exit> python /usr/lib/python3.12/site-packages/pyproject_api/_backend.py True setuptools.build_meta
  py312: FAIL code 1 (7.96=setup[4.30]+cmd[3.66] seconds)
  evaluation failed :( (8.02 seconds)

See also:

https://docs.python.org/3/library/datetime.html#datetime.datetime.utcnow

python/cpython#103857

https://discuss.python.org/t/deprecating-utcnow-and-utcfromtimestamp/26221/14

[merkys]

I attempted to replace datetime.datetime.utcnow() calls with datetime.datetime.now(datetime.UTC), but I get the following failure for Python 3.12:

self = <tests.opc.parts.test_coreprops.DescribeCorePropertiesPart object at 0x7f2c29bda960>

    def it_can_create_a_default_core_properties_part(self):
        core_properties_part = CorePropertiesPart.default(None)
        assert isinstance(core_properties_part, CorePropertiesPart)
        core_properties = core_properties_part.core_properties
        assert core_properties.title == "Word Document"
        assert core_properties.last_modified_by == "python-docx"
        assert core_properties.revision == 1
>       delta = datetime.now(UTC) - core_properties.modified
E       TypeError: can't subtract offset-naive and offset-aware datetimes

I have no idea how to fix this, alas.

[msebas]

I got the test running with delta = datetime.now(UTC).replace(tzinfo=None) - core_properties.modified.