the asynctest library used in test suite is abandoned, not supported with Python 3.9+

[Apteryks]

All is in the title; see: Martiusweb/asynctest#158.

[swamper123]

I would recommened to replace asynctest with pytest-asyncio which is a plugin for pytest.

In later future versions we may be able to switch to the inbuilt solution from python, since unittests supports async stuff in ... 3.9 I guess? But that second thing is still up in the air.

[janiversen]

is removed on dev.