Fails to discover pytest tests in Pytest > 5.1.0

[dillonm197]

I'm not sure if this is an issue with pytest so I'm logging it here for now. Tests fail to discover when using pytest >= 5.1.0 when pytest.ini or tox.ini are present in project.

I'd normally assume this was a pytest issue but if I execute the command to discover tests manually in terminal, it runs without error.

Environment data

• VS Code version: 1.37.1
• Extension version: 2019.9.32431-dev
• OS and version: Windows 10 Pro (64 bit)
• Python version: 3.7.3 32-bit
• Relevant/affected Python packages and their versions: pytest >= 5.1.0

Expected behaviour

Test discovery passes.

Actual behaviour

Test discovery fails.

Steps to reproduce:

1. Create a Python project that utilizes pytest.
2. Add pytest.ini.
3. Add conftest.py.
4. In conftest.py add the following:

def pytest_addoption(parser):
    parser.addoption('--test', action='store', default='test', help='Test')

5. Create a test file and add simple tests to it.
6. Open the test tab and scan for tests.

Logs

python C:\Users\dillon.miller\.vscode\extensions\ms-python.python-2019.9.32431-dev\pythonFiles\testing_tools\run_adapter.py discover pytest -- -s --cache-clear tests
Test Discovery failed: 
Error: ============================= test session starts =============================
platform win32 -- Python 3.7.3, pytest-5.1.1, py-1.8.0, pluggy-0.12.0
rootdir: c:\Users\dillon.miller\Documents\act.nexus\e2e, inifile: tox.ini
plugins: flaky-3.6.1, check-0.3.5, html-1.22.0, instafail-0.4.1, metadata-1.8.0
________________________ ERROR collecting test session ________________________
Traceback (most recent call last):
  File "C:\Users\dillon.miller\AppData\Local\Programs\Python\Python37-32\lib\site-packages\_pytest\config\__init__.py", line 436, in _importconftest
    return self._conftestpath2mod[conftestpath]
KeyError: local('C:\\Users\\dillon.miller\\Documents\\act.nexus\\e2e\\conftest.py')

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\dillon.miller\AppData\Roaming\Python\Python37\site-packages\py\_path\common.py", line 377, in visit
    for x in Visitor(fil, rec, ignore, bf, sort).gen(self):
  File "C:\Users\dillon.miller\AppData\Roaming\Python\Python37\site-packages\py\_path\common.py", line 418, in gen
    dirs = self.optsort([p for p in entries
  File "C:\Users\dillon.miller\AppData\Roaming\Python\Python37\site-packages\py\_path\common.py", line 419, in <listcomp>
    if p.check(dir=1) and (rec is None or rec(p))])
  File "C:\Users\dillon.miller\AppData\Local\Programs\Python\Python37-32\lib\site-packages\_pytest\main.py", line 600, in _recurse
    ihook = self.gethookproxy(dirpath.dirpath())
  File "C:\Users\dillon.miller\AppData\Local\Programs\Python\Python37-32\lib\site-packages\_pytest\main.py", line 424, in gethookproxy
    my_conftestmodules = pm._getconftestmodules(fspath)
  File "C:\Users\dillon.miller\AppData\Local\Programs\Python\Python37-32\lib\site-packages\_pytest\config\__init__.py", line 420, in _getconftestmodules
    mod = self._importconftest(conftestpath.realpath())
  File "C:\Users\dillon.miller\AppData\Local\Programs\Python\Python37-32\lib\site-packages\_pytest\config\__init__.py", line 461, in _importconftest
    self.consider_conftest(mod)
  File "C:\Users\dillon.miller\AppData\Local\Programs\Python\Python37-32\lib\site-packages\_pytest\config\__init__.py", line 514, in consider_conftest
    self.register(conftestmodule, name=conftestmodule.__file__)
  File "C:\Users\dillon.miller\AppData\Local\Programs\Python\Python37-32\lib\site-packages\_pytest\config\__init__.py", line 323, in register
    ret = super().register(plugin, name)
  File "C:\Users\dillon.miller\AppData\Roaming\Python\Python37\site-packages\pluggy\manager.py", line 121, in register
    hook._maybe_apply_history(hookimpl)
  File "C:\Users\dillon.miller\AppData\Roaming\Python\Python37\site-packages\pluggy\hooks.py", line 336, in _maybe_apply_history
    res = self._hookexec(self, [method], kwargs)
  File "C:\Users\dillon.miller\AppData\Roaming\Python\Python37\site-packages\pluggy\manager.py", line 87, in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
  File "C:\Users\dillon.miller\AppData\Roaming\Python\Python37\site-packages\pluggy\manager.py", line 81, in <lambda>
    firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
  File "C:\Users\dillon.miller\AppData\Roaming\Python\Python37\site-packages\pluggy\callers.py", line 208, in _multicall
    return outcome.get_result()
  File "C:\Users\dillon.miller\AppData\Roaming\Python\Python37\site-packages\pluggy\callers.py", line 80, in get_result
    raise ex[1].with_traceback(ex[2])
  File "C:\Users\dillon.miller\AppData\Roaming\Python\Python37\site-packages\pluggy\callers.py", line 187, in _multicall
    res = hook_impl.function(*args)
  File "c:\Users\dillon.miller\Documents\act.nexus\e2e\conftest.py", line 86, in pytest_addoption
    help='Test')
  File "C:\Users\dillon.miller\AppData\Local\Programs\Python\Python37-32\lib\site-packages\_pytest\config\argparsing.py", line 73, in addoption
    self._anonymous.addoption(*opts, **attrs)
  File "C:\Users\dillon.miller\AppData\Local\Programs\Python\Python37-32\lib\site-packages\_pytest\config\argparsing.py", line 304, in addoption
    raise ValueError("option names %s already added" % conflict)
ValueError: option names {'--test'} already added
collected 0 items / 1 errors

- generated html file: file://c:\Users\dillon.miller\Documents\act.nexus\e2e\pytest-results.html -
!!!!!!!!!!!!!!!!!!! Interrupted: 1 errors during collection !!!!!!!!!!!!!!!!!!!
============================== 1 error in 0.23s ===============================

Traceback (most recent call last):
  File "C:\Users\dillon.miller\.vscode\extensions\ms-python.python-2019.9.32431-dev\pythonFiles\testing_tools\run_adapter.py", line 18, in <module>
    main(tool, cmd, subargs, toolargs)
  File "C:\Users\dillon.miller\.vscode\extensions\ms-python.python-2019.9.32431-dev\pythonFiles\testing_tools\adapter\__main__.py", line 90, in main
    parents, result = run(toolargs, **subargs)
  File "C:\Users\dillon.miller\.vscode\extensions\ms-python.python-2019.9.32431-dev\pythonFiles\testing_tools\adapter\pytest\_discovery.py", line 35, in discover
    raise Exception('pytest discovery failed (exit code {})'.format(ec))
Exception: pytest discovery failed (exit code 2)

[ericsnowcurrently]

Thanks for letting us know about this. We are aware of the issue and addressing it in #6990.