Error "No module named 'py'" when running tests on a remote host using a socket server

In order to assess xdist when it comes to execution on remote host, I tried to do what is described here https://github.com/pytest-dev/pytest-xdist#sending-tests-to-remote-socket-servers with a really simple test as described below and received the following error in my client.

File "", line 1, in do_exec
File "", line 13, in
ModuleNotFoundError: No module named 'py'

• test:

import unittest
from mypkg.a_file import print_stuff


class Test(unittest.TestCase):

    def test_it(self):
        print_stuff()
        self.assertTrue(True)

• project tree:

C:.
│ pytest.ini
│ setup.cfg
│
├───.cache
│ └───v
│ └───cache
│ lastfailed
│
├───.pytest_cache
│ │ .gitignore
│ │ CACHEDIR.TAG
│ │ README.md
│ │
│ └───v
│ └───cache
│ nodeids
│ stepwise
│
├───assets
│ style.css
│
├───mypkg
│ │ a_file.py
│ │ init.py
│ │
│ └───pycache
│ a_file.cpython-36.pyc
│ a_file.cpython-37.pyc
│ init.cpython-36.pyc
│ init.cpython-37.pyc
│
└───test
│ init.py
│
├───mypkg
│ │ test_.py
│ │ init.py
│ │
│ └───pycache
│ test_.cpython-36-pytest-5.0.1.pyc
│ test_.cpython-37-PYTEST.pyc
│ init.cpython-36.pyc
│ init.cpython-37.pyc
│
└───pycache
init.cpython-36.pyc
init.cpython-37.pyc

• pytest.ini

[pytest]
addopts = --html=remote-results.html --junitxml=remote-results.html --log-level=INFO --tx socket={myhost}:8888

• setup.cfg

[tool:pytest]
rsyncdirs = . mypkg

• When running on my local machine:

python -m pytest

===================================================== test session starts ====================================================== platform win32 -- Python 3.6.7, pytest-5.0.1, py-1.8.0, pluggy-0.12.0
rootdir: \test, inifile: pytest.ini
plugins: forked-1.0.2, html-1.21.1, metadata-1.8.0, xdist-1.29.0
collected 1 item

test\mypkg\test_.py . [100%]

------------- generated xml file: remote-results.html -------------- --------- generated html file: file:\remote-results.html ---------- =================================================== 1 passed in 0.20 seconds ===================================================

• When running on a remote host with socketserver.py running there:

python -m pytest -d --rsyncdir mypkg mypkg

try: execmodel
except NameError:
execmodel = get_execmodel('thread')
io = SocketIO(clientsock, execmodel)
io.write('1'.encode('ascii'))
serve(io, id='socket={myhost}:8888-slave')", line 1063, in executetask
File "", line 1, in do_exec
File "", line 13, in
ModuleNotFoundError: No module named 'py'

replacing crashed worker gw0

Start with the pytest-xdist remote socket-server instructions and reproduce the failure using socketserver.py with the shown pytest.ini and setup.cfg. Trace the remote exec path where the worker imports py; done means the remote socket test runs without ModuleNotFoundError and the sample test passes.