Created attachment 1561528 [details]
Full log from Copr

When I rebuild python-more-executors 2.0.1-2.fc31 with Python 3.8, I get:

=================================== FAILURES ===================================
___________________________________ test_run ___________________________________

asyncio = <module 'asyncio' from '/usr/lib64/python3.8/asyncio/__init__.py'>

    def test_run(asyncio):
        with AsyncioExecutor(Executors.thread_pool()) as executor:
            f = executor.submit(sleep_then_return, 0.01, 'abc')
    
            # The result should not be available yet
>           assert_that(calling(f.result), raises(asyncio.futures.InvalidStateError))
E           AttributeError: module 'asyncio.futures' has no attribute 'InvalidStateError'

tests/test_asyncio.py:30: AttributeError
============== 1 failed, 1627 passed, 8 skipped in 70.50 seconds ===============


Apparently, this exception is available from asyncio, not asyncio.futures (that was merely a leaking import):

    $ python3.7 -c 'import asyncio; asyncio.futures.InvalidStateError'
    $ python3.8 -c 'import asyncio; asyncio.futures.InvalidStateError'
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    AttributeError: module 'asyncio.futures' has no attribute 'InvalidStateError'


    $ python3.8 -c 'import asyncio; asyncio.InvalidStateError'
    $ python3.7 -c 'import asyncio; asyncio.InvalidStateError'
    $ python3.6 -c 'import asyncio; asyncio.InvalidStateError'
    $ python3.5 -c 'import asyncio; asyncio.InvalidStateError'
    $ python3.4 -c 'import asyncio; asyncio.InvalidStateError'

Full log attached.