python-subprocess-tee fails to build with Python 3.10.0b1:

...
lib/subprocess_tee/test/test_rich.py:20: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
args = 'echo 123', kwargs = {}, cmd = 'echo 123'
    def run(args: Union[str, List[str]], **kwargs: Any) -> CompletedProcess:
        """Drop-in replacement for subprocerss.run that behaves like tee.
    
        Extra arguments added by our version:
        echo: False - Prints command before executing it.
        quiet: False - Avoid printing output
        """
        if isinstance(args, str):
            cmd = args
        else:
            # run was called with a list instead of a single item but asyncio
            # create_subprocess_shell requires command as a single string, so
            # we need to convert it to string
            cmd = join(args)
    
        if kwargs.get("echo", False):
            print(f"COMMAND: {cmd}")
    
>       loop = asyncio.get_event_loop()
E       DeprecationWarning: There is no current event loop

...
FAILED lib/subprocess_tee/test/test_rich.py::test_rich_console_ex - Deprecati...
FAILED lib/subprocess_tee/test/test_rich.py::test_rich_console_ex_ansi - Depr...
FAILED lib/subprocess_tee/test/test_unit.py::test_run_string - DeprecationWar...
FAILED lib/subprocess_tee/test/test_unit.py::test_run_list - DeprecationWarni...
FAILED lib/subprocess_tee/test/test_unit.py::test_run_echo - DeprecationWarni...
FAILED lib/subprocess_tee/test/test_unit.py::test_run_with_env[auto] - Deprec...
FAILED lib/subprocess_tee/test/test_unit.py::test_run_with_env[sh] - Deprecat...
FAILED lib/subprocess_tee/test/test_unit.py::test_run_with_env[bash] - Deprec...
FAILED lib/subprocess_tee/test/test_unit.py::test_run_with_env[zsh] - Depreca...
FAILED lib/subprocess_tee/test/test_unit.py::test_run_shell - DeprecationWarn...
FAILED lib/subprocess_tee/test/test_unit.py::test_run_shell_undefined - Depre...
FAILED lib/subprocess_tee/test/test_unit.py::test_run_cwd - DeprecationWarnin...
============================== 12 failed in 0.39s ==============================


https://docs.python.org/3.10/whatsnew/3.10.html#deprecated
"""
asyncio.get_event_loop() now emits a deprecation warning if there is no running event loop. In the future it will be an alias of get_running_loop(). asyncio functions which implicitly create a Future or Task objects now emit a deprecation warning if there is no running event loop and no explicit loop argument is passed: ensure_future(), wrap_future(), gather(), shield(), as_completed() and constructors of Future, Task, StreamReader, StreamReaderProtocol.
"""
https://bugs.python.org/issue39529

For the build logs, see:
https://copr-be.cloud.fedoraproject.org/results/@python/python3.10/fedora-rawhide-x86_64/02172425-python-subprocess-tee/

For all our attempts to build python-subprocess-tee with Python 3.10, see:
https://copr.fedorainfracloud.org/coprs/g/python/python3.10/package/python-subprocess-tee/

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 3.10:
https://copr.fedorainfracloud.org/coprs/g/python/python3.10/

Let us know here if you have any questions.

Python 3.10 will be included in Fedora 35. To make that update smoother, we're building Fedora packages with early pre-releases of Python 3.10.
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.