pytest_namespace removed from pytest since 4.0

[arunisaac]

pytest_namespace has been removed from pytest since 4.0. See https://docs.pytest.org/en/latest/deprecations.html#pytest-namespace This causes the tests to fail with the following error.

============================= test session starts ==============================
platform linux -- Python 3.7.4, pytest-4.4.2, py-1.8.0, pluggy-0.11.0
hypothesis profile 'default' -> database=DirectoryBasedExampleDatabase('/tmp/guix-build-unknown-horizons-2019.1.drv-0/unknown-horizons-2019.1/.hypothesis/examples')
rootdir: /tmp/guix-build-unknown-horizons-2019.1.drv-0/unknown-horizons-2019.1
plugins: hypothesis-4.18.3, mock-1.10.1
INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "/gnu/store/wrllykvq4l9ia5wldivmdlwgf2c8m2mb-python-pytest-4.4.2/lib/python3.7/site-packages/_pytest/main.py", line 209, in wrap_session
INTERNALERROR>     session.exitstatus = doit(config, session) or 0
INTERNALERROR>   File "/gnu/store/wrllykvq4l9ia5wldivmdlwgf2c8m2mb-python-pytest-4.4.2/lib/python3.7/site-packages/_pytest/main.py", line 248, in _main
INTERNALERROR>     config.hook.pytest_collection(session=session)
INTERNALERROR>   File "/gnu/store/w80vzg9kysnk379pn71b7pgn6l2jr6dx-python-pluggy-0.11.0/lib/python3.7/site-packages/pluggy/hooks.py", line 289, in __call__
INTERNALERROR>     return self._hookexec(self, self.get_hookimpls(), kwargs)
INTERNALERROR>   File "/gnu/store/w80vzg9kysnk379pn71b7pgn6l2jr6dx-python-pluggy-0.11.0/lib/python3.7/site-packages/pluggy/manager.py", line 68, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR>   File "/gnu/store/w80vzg9kysnk379pn71b7pgn6l2jr6dx-python-pluggy-0.11.0/lib/python3.7/site-packages/pluggy/manager.py", line 62, in <lambda>
INTERNALERROR>     firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
INTERNALERROR>   File "/gnu/store/w80vzg9kysnk379pn71b7pgn6l2jr6dx-python-pluggy-0.11.0/lib/python3.7/site-packages/pluggy/callers.py", line 208, in _multicall
INTERNALERROR>     return outcome.get_result()
INTERNALERROR>   File "/gnu/store/w80vzg9kysnk379pn71b7pgn6l2jr6dx-python-pluggy-0.11.0/lib/python3.7/site-packages/pluggy/callers.py", line 80, in get_result
INTERNALERROR>     raise ex[1].with_traceback(ex[2])
INTERNALERROR>   File "/gnu/store/w80vzg9kysnk379pn71b7pgn6l2jr6dx-python-pluggy-0.11.0/lib/python3.7/site-packages/pluggy/callers.py", line 187, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "/gnu/store/wrllykvq4l9ia5wldivmdlwgf2c8m2mb-python-pytest-4.4.2/lib/python3.7/site-packages/_pytest/main.py", line 258, in pytest_collection
INTERNALERROR>     return session.perform_collect()
INTERNALERROR>   File "/gnu/store/wrllykvq4l9ia5wldivmdlwgf2c8m2mb-python-pytest-4.4.2/lib/python3.7/site-packages/_pytest/main.py", line 495, in perform_collect
INTERNALERROR>     self.config.pluginmanager.check_pending()
INTERNALERROR>   File "/gnu/store/w80vzg9kysnk379pn71b7pgn6l2jr6dx-python-pluggy-0.11.0/lib/python3.7/site-packages/pluggy/manager.py", line 251, in check_pending
INTERNALERROR>     % (name, hookimpl.plugin),
INTERNALERROR> pluggy.manager.PluginValidationError: unknown hook 'pytest_namespace' in plugin <module 'tests.conftest' from '/tmp/guix-build-unknown-horizons-2019.1.drv-0/unknown-horizons-2019.1/tests/conftest.py'>

========================= 3 warnings in 43.61 seconds ==========================
command "pytest" "tests" failed with status 3

Some refactoring maybe in order. Thank you!