Bug: Plugin needs `pynvim` installed in activated venv

Describe the bug
I tried to make it run and it does work now - however I had to install pynvim in the venv I am using for my projects - it is installed in my main environment but for some reason ultest does only consider my venv-interpreter. As I work with poetry, this would imply I needed to install the module in each project, which is a minor annoyance but I would like to know whether it's not possible to separate some of the calls that reference the editor functionality. I see in

vim-ultest/rplugin/python3/ultest/__init__.py

Line 65 in 45f2b2f

from pynvim import Nvim, function, plugin

for example that you import pynvim there, I assume that happens with the $VIRTUAL_ENV interpreter, which is called if you do these calls here:

vim-ultest/autoload/ultest/handler.vim

Line 35 in b2b9caf

call s:Call('_ultest_run_all', a:000)

This is not a "bug" per se but I'd say it's a desirable behaviour! :)

To Reproduce
Steps to reproduce the behavior:

Install vim-ultest with packer
install pynvim in system interpreter
create new venv, install pytest and activate it
configure pytest as test launcher in config file
launch nvim on file containing tests

Expected behavior
vim-ultest works if the currently activated venv is not using pynvim and sources the interpreter defined in g:python3_host_prog instead to prevent the (small) issue of installing pynvim into all projects.

I take it back. I defined vim.g.python3_host_prog = '/usr/bin/python' in .config/nvim/after/ftplugin/python.lua and that gets loaded too late apparently. All good now, great plugin :)