TestConfigurationWatcher tests fail with pytest 3.10 for python2

[sdelafond]

All the tests in TestConfigurationWatcher fail the same way with pytest 3.10:

pytest -vvv -k test_should_check
=================================================================================================================================== test session starts ===================================================================================================================================
platform linux2 -- Python 2.7.15+, pytest-3.10.1, py-1.7.0, pluggy-0.8.0 -- /usr/bin/python2
cachedir: .pytest_cache
hypothesis profile 'default' -> database=DirectoryBasedExampleDatabase('/home/seb/vcs/pystaticconfiguration/.hypothesis/examples')
rootdir: /home/seb/vcs/pystaticconfiguration, inifile:
plugins: hypothesis-3.71.11
collected 142 items / 141 deselected

tests/config_test.py::TestConfigurationWatcher::test_should_check
INTERNALERROR> Traceback (most recent call last):
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/_pytest/main.py", line 184, in wrap_session
INTERNALERROR> session.exitstatus = doit(config, session) or 0
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/_pytest/main.py", line 224, in _main
INTERNALERROR> config.hook.pytest_runtestloop(session=session)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/hooks.py", line 284, in call
INTERNALERROR> return self._hookexec(self, self.get_hookimpls(), kwargs)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/manager.py", line 67, in _hookexec
INTERNALERROR> return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/manager.py", line 61, in
INTERNALERROR> firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/callers.py", line 208, in _multicall
INTERNALERROR> return outcome.get_result()
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/callers.py", line 81, in get_result
INTERNALERROR> _reraise(*ex) # noqa
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/callers.py", line 187, in _multicall
INTERNALERROR> res = hook_impl.function(*args)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/_pytest/main.py", line 245, in pytest_runtestloop
INTERNALERROR> item.config.hook.pytest_runtest_protocol(item=item, nextitem=nextitem)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/hooks.py", line 284, in call
INTERNALERROR> return self._hookexec(self, self.get_hookimpls(), kwargs)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/manager.py", line 67, in _hookexec
INTERNALERROR> return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/manager.py", line 61, in
INTERNALERROR> firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/callers.py", line 208, in _multicall
INTERNALERROR> return outcome.get_result()
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/callers.py", line 81, in get_result
INTERNALERROR> _reraise(*ex) # noqa
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/pluggy/callers.py", line 187, in _multicall
INTERNALERROR> res = hook_impl.function(*args)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/_pytest/runner.py", line 77, in pytest_runtest_protocol
INTERNALERROR> runtestprotocol(item, nextitem=nextitem)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/_pytest/runner.py", line 86, in runtestprotocol
INTERNALERROR> rep = call_and_report(item, "setup", log)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/_pytest/runner.py", line 173, in call_and_report
INTERNALERROR> hook = item.ihook
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/_pytest/nodes.py", line 118, in ihook
INTERNALERROR> return self.session.gethookproxy(self.fspath)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/_pytest/main.py", line 418, in gethookproxy
INTERNALERROR> my_conftestmodules = pm._getconftestmodules(fspath)
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/_pytest/config/init.py", line 409, in _getconftestmodules
INTERNALERROR> for parent in directory.realpath().parts():
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/py/_path/local.py", line 588, in realpath
INTERNALERROR> return self.class(os.path.realpath(self.strpath))
INTERNALERROR> File "/usr/lib/python2.7/dist-packages/py/_path/local.py", line 154, in init
INTERNALERROR> raise ValueError("can only pass None, Path instances "
INTERNALERROR> ValueError: can only pass None, Path instances or non-empty strings to LocalPath

For reference, this is debian bug #915765 (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=915765).

[sdelafond]

The issue is somewhere in setup_mocks_and_config_watcher(), so #103 came to mind, but FTR all the tests are passing using pytest-3 3.10, so this issue really is limited to pytest-2.