Dash Testing Waitress: Server not starting correctly

Hi all,

I am trying to run my dash tests using the dash_process_server. However, the server is not starting up correctly.

I have created the following fixture in pytest (analogue to the test fixture in dash_table on github)
def test_waitress(request, dash_process_server, tmpdir):
with DataTableComposite(
) as dc:
yield dc

and start the server inside my test via test_waitress.start_server(app)

Looking at the debugger I see that waitress is called on the command line with the following command:
waitress-serve --listen= <dash.dash.Dash object at 0x7f4506d8a50>:app.server

So it seems that I would need to pass the path to my module instead of the dash app. However that makes me wonder whether this is the right way to run tests via waitress anyway.

Also I would like to run my tests with multiple processes (waitress is only running multi-thread) because I experienced several occasions where an app would run fine single-process but run into infinite recursions in multi-process. Is there anyway to run tests with multiple processes right now?

Thanks for any hints!