Can't iterate over multiprocessing.managers.DictProxy - python-3.x

Question

Can't iterate over multiprocessing.managers.DictProxy. through pytest-paralell but works fine in python.
I found this issue even here https://bugs.python.org/issue9733 but since the managers.py is Read-Only; I cannot do changes there. Has anybody faced this issue earlier ? How can I resolve it ?
test_Run.py
from multiprocessing import Process, Manager
def f(d, l):
d[1] = '1'
d['2'] = 2
d[0.25] = None
l.reverse()
if __name__ == '__main__':
with Manager() as manager:
d = manager.dict()
l = manager.list(range(10))
p = Process(target=f, args=(d, l))
p.start()
p.join()
print(d)
print(l)
If you run the
(venv) [tivo#localhost src]$ python test_run.py
{0.25: None, 1: '1', '2': 2}
[9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
(venv) [tivo#localhost src]$
EDITED:
If you run this with pytest with the following code.
from multiprocessing import Process, Manager
def test_f():
d, l = {}, []
d[1] = '1'
d['2'] = 2
d[0.25] = None
print(d)
with Manager() as manager:
d = manager.dict()
l = manager.list(range(10))
l.reverse()
print(l)
p = Process(target=f)
p.start()
p.join()
(venv) [tivo#localhost src]$ pytest -v -s test_run.py
collecting ... [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
{0.25: None, 1: '1', '2': 2}
collected 1 item
test_run.py::test_f {0.25: None, 1: '1', '2': 2}
PASSED
(venv) [tivo#localhost src]$
But If you run through pytest along with pytest-paralell package, it throws error
(venv) [tivo#localhost src]$ pytest -v -s --tests-per-worker auto --workers auto test_run.py
===================================================================== test session starts ======================================================================
platform linux -- Python 3.4.4, pytest-4.5.0, py-1.8.0, pluggy-0.11.0 -- /home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/bin/python3
cachedir: .pytest_cache
rootdir: /home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/src, inifile: pytest.ini
plugins: xdist-1.28.0, remotedata-0.3.1, pipeline-0.3.0, parallel-0.0.9, forked-1.0.2, flake8-1.0.4, cov-2.7.1
collecting ... [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
{0.25: None, 1: '1', '2': 2}
collected 1 item
pytest-parallel: 2 workers (processes), 0 test per worker (thread)
Traceback (most recent call last):
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/bin/pytest", line 10, in <module>
sys.exit(main())
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/_pytest/config/__init__.py", line 79, in main
return config.hook.pytest_cmdline_main(config=config)
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/pluggy/hooks.py", line 289, in __call__
return self._hookexec(self, self.get_hookimpls(), kwargs)
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/pluggy/manager.py", line 68, in _hookexec
return self._inner_hookexec(hook, methods, kwargs)
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/pluggy/manager.py", line 62, in <lambda>
firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/pluggy/callers.py", line 208, in _multicall
return outcome.get_result()
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/pluggy/callers.py", line 80, in get_result
raise ex[1].with_traceback(ex[2])
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/pluggy/callers.py", line 187, in _multicall
res = hook_impl.function(*args)
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/_pytest/main.py", line 242, in pytest_cmdline_main
return wrap_session(config, _main)
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/_pytest/main.py", line 235, in wrap_session
session=session, exitstatus=session.exitstatus
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/pluggy/hooks.py", line 289, in __call__
return self._hookexec(self, self.get_hookimpls(), kwargs)
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/pluggy/manager.py", line 68, in _hookexec
return self._inner_hookexec(hook, methods, kwargs)
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/pluggy/manager.py", line 62, in <lambda>
firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/pluggy/callers.py", line 203, in _multicall
gen.send(outcome)
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/_pytest/terminal.py", line 678, in pytest_sessionfinish
self.summary_stats()
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/_pytest/terminal.py", line 876, in summary_stats
(line, color) = build_summary_stats_line(self.stats)
File "/home/tivo/workspace/ServicePortal/autotestscripts/CAT/scripts/ServerQE/brat/venv/lib/python3.4/site-packages/_pytest/terminal.py", line 1034, in build_summary_stats_line
for found_type in stats:
File "<string>", line 2, in __getitem__
File "/usr/local/lib/python3.4/multiprocessing/managers.py", line 747, in _callmethod
raise convert_to_error(kind, result)
KeyError: 0
(venv) [tivo#localhost src]$
I have the following packages with me
pytest-parallel==0.0.9
pytest-pipeline==0.3.0
Q. What workaround can I do to get this above code PASSED without Error logs ? The issue being the results are not giving me output as to how many test cases are PASSED.
Why is it taking pytest-parallel: 2 workers (processes), 1 test per worker (thread) ? I have provided only one function there !
HINT:
If I add flags --worker 1; this above error does not appear; but usually fails my scripts and hence I am forced to use --tests-per-worker 1 along with it. But paralellism is not present here !