python-pynetdicom fails to build with Python 3.9.0a2.

_________________ TestAEGoodAssociation.test_associate_max_pdu _________________
self = <pynetdicom.tests.test_ae.TestAEGoodAssociation object at 0x7ff18cfe0d90>
    def test_associate_max_pdu(self):
        """ Check Association has correct max PDUs on either end """
        self.ae = ae = AE()
        ae.acse_timeout = 5
        ae.dimse_timeout = 5
        ae.network_timeout = 5
        ae.maximum_pdu_size = 54321
        ae.add_supported_context(VerificationSOPClass)
        scp = ae.start_server(('', 11112), block=False)
    
        scu_ae = AE()
        scu_ae.acse_timeout = 5
        scu_ae.dimse_timeout = 5
        scu_ae.network_timeout = 5
        scu_ae.add_requested_context(VerificationSOPClass)
        assoc = scu_ae.associate('localhost', 11112, max_pdu=12345)
        assert assoc.is_established
    
        assert scp.active_associations[0].acceptor.maximum_length == (
            54321
        )
        assert scp.active_associations[0].requestor.maximum_length == (
            12345
        )
        assert assoc.requestor.maximum_length == 12345
        assert assoc.acceptor.maximum_length == 54321
        assoc.release()
    
        # Check 0 max pdu value - max PDU value maps to 0x10000 internally
        assoc = scu_ae.associate('localhost', 11112, max_pdu=0)
        assert assoc.requestor.maximum_length == 0
>       assert scp.active_associations[0].requestor.maximum_length == 0
E       assert 12345 == 0
E        +  where 12345 = <pynetdicom.association.ServiceUser object at 0x7ff18cf9fbe0>.maximum_length
E        +    where <pynetdicom.association.ServiceUser object at 0x7ff18cf9fbe0> = <Association(AcceptorThread@20200122170341, started daemon 140675406731008)>.requestor
pynetdicom/tests/test_ae.py:388: AssertionError



For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.9/fedora-rawhide-x86_64/01173191-python-pynetdicom/

For all our attempts to build python-pynetdicom with Python 3.9, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.9/package/python-pynetdicom/

Testing and mass rebuild of packages is happening in copr. You can follow these instructions to test locally in mock if your package builds with Python 3.9:
https://copr.fedorainfracloud.org/coprs/g/python/python3.9/

Let us know here if you have any questions.

Python 3.9 will be included in Fedora 33. To make that update smoother, we're building Fedora packages with early pre-releases of Python 3.9.
A build failure prevents us from testing all dependent packages (transitive [Build]Requires), so if this package is required a lot, it's important for us to get it fixed soon.
We'd appreciate help from the people who know this package best, but if you don't want to work on this now, let us know so we can try to work around it on our side.