pytest.mark.parametrize over None and empty dict

[andreacassioli]

I am trying to run tests like the following

@pytest.mark.parametrize('y,shipment', [None])
@pytest.mark.parametrize('x', [None])
def test_foo(x, y):
    #whatever

I get a very criptic long error as follow

---------------------------------------------------------------------------------------------------------------------------------------------- generated xml file: /Users/aca286/workspace/protomorph/tests.xml ----------------------------------------------------------------------------------------------------------------------------------------------------
================================================================================================================================================================================= ERRORS =================================================================================================================================================================================
________________________________________________________________________________________________________________________________________________________ ERROR collecting app/tests/data/test_cost_calculation.py ________________________________________________________________________________________________________________________________________________________
../../anaconda3/lib/python3.6/site-packages/_pytest/runner.py:196: in __init__
    self.result = func()
../../anaconda3/lib/python3.6/site-packages/_pytest/runner.py:375: in <lambda>
    lambda: list(collector.collect()),
../../anaconda3/lib/python3.6/site-packages/_pytest/python.py:389: in collect
    return super(Module, self).collect()
../../anaconda3/lib/python3.6/site-packages/_pytest/python.py:330: in collect
    res = self.makeitem(name, obj)
../../anaconda3/lib/python3.6/site-packages/_pytest/python.py:342: in makeitem
    collector=self, name=name, obj=obj)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:745: in __call__
    return self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:339: in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:334: in <lambda>
    _MultiCall(methods, kwargs, hook.spec_opts).execute()
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:613: in execute
    return _wrapped_call(hook_impl.function(*args), self.execute)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:250: in _wrapped_call
    wrap_controller.send(call_outcome)
../../anaconda3/lib/python3.6/site-packages/_pytest/python.py:188: in pytest_pycollect_makeitem
    res = list(collector._genfunctions(name, obj))
../../anaconda3/lib/python3.6/site-packages/_pytest/python.py:362: in _genfunctions
    self.ihook.pytest_generate_tests(metafunc=metafunc)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:745: in __call__
    return self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:339: in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:334: in <lambda>
    _MultiCall(methods, kwargs, hook.spec_opts).execute()
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:614: in execute
    res = hook_impl.function(*args)
../../anaconda3/lib/python3.6/site-packages/_pytest/python.py:113: in pytest_generate_tests
    metafunc.parametrize(*marker.args, **marker.kwargs)
../../anaconda3/lib/python3.6/site-packages/_pytest/python.py:833: in parametrize
    ids = idmaker(argnames, parameters, idfn, ids, self.config)
../../anaconda3/lib/python3.6/site-packages/_pytest/python.py:958: in idmaker
    for valindex, parameterset in enumerate(parametersets)]
../../anaconda3/lib/python3.6/site-packages/_pytest/python.py:958: in <listcomp>
    for valindex, parameterset in enumerate(parametersets)]
../../anaconda3/lib/python3.6/site-packages/_pytest/python.py:950: in _idvalset
    for val, argname in zip(parameterset.values, argnames)]
E   TypeError: zip argument #1 must support iteration```

I am running on

11:27 $ python
Python 3.6.3 | packaged by conda-forge | (default, Nov  4 2017, 10:13:32) 
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 

and

pytest==3.2.1
pytest-cov==2.6.0

what am I missing?

[RonnyPfannschmidt]

@pytest.mark.parametrize('y,shipment', [None]) <- should be [(None, None)] as you have 2 parameter names there

[RonnyPfannschmidt]

but the error message could be better as well

after all its pretty non-indicative

[andreacassioli]

@RonnyPfannschmidt thanks. However, I also tried

@pytest.mark.parametrize('x', [None])
@pytest.mark.parametrize('y', [None])
def test_foo(x, y):
    #whatever
    pass

and got

_________________________________________________________________________________________________________________________________________________________________ ERROR at setup of test_foo[None-None] __________________________________________________________________________________________________________________________________________________________________

self = <CallInfo when='setup' exception: 'dict' object has no attribute 'param'>, func = <function call_runtest_hook.<locals>.<lambda> at 0x109cb4ea0>, when = 'setup'

    def __init__(self, func, when):
        #: context of invocation: one of "setup", "call",
        #: "teardown", "memocollect"
        self.when = when
        self.start = time()
        try:
>           self.result = func()

../../anaconda3/lib/python3.6/site-packages/_pytest/runner.py:196: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
../../anaconda3/lib/python3.6/site-packages/_pytest/runner.py:182: in <lambda>
    return CallInfo(lambda: ihook(item=item, **kwds), when=when)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:745: in __call__
    return self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:339: in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:334: in <lambda>
    _MultiCall(methods, kwargs, hook.spec_opts).execute()
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:613: in execute
    return _wrapped_call(hook_impl.function(*args), self.execute)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:254: in _wrapped_call
    return call_outcome.get_result()
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:279: in get_result
    raise ex[1].with_traceback(ex[2])
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:265: in __init__
    self.result = func()
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:614: in execute
    res = hook_impl.function(*args)
../../anaconda3/lib/python3.6/site-packages/_pytest/runner.py:106: in pytest_runtest_setup
    item.session._setupstate.prepare(item)
../../anaconda3/lib/python3.6/site-packages/_pytest/runner.py:500: in prepare
    col.setup()
../../anaconda3/lib/python3.6/site-packages/_pytest/python.py:1175: in setup
    fixtures.fillfixtures(self)
../../anaconda3/lib/python3.6/site-packages/_pytest/fixtures.py:243: in fillfixtures
    request._fillfixtures()
../../anaconda3/lib/python3.6/site-packages/_pytest/fixtures.py:386: in _fillfixtures
    item.funcargs[argname] = self.getfixturevalue(argname)
../../anaconda3/lib/python3.6/site-packages/_pytest/fixtures.py:428: in getfixturevalue
    return self._get_active_fixturedef(argname).cached_result[0]
../../anaconda3/lib/python3.6/site-packages/_pytest/fixtures.py:453: in _get_active_fixturedef
    result = self._getfixturevalue(fixturedef)
../../anaconda3/lib/python3.6/site-packages/_pytest/fixtures.py:518: in _getfixturevalue
    val = fixturedef.execute(request=subrequest)
../../anaconda3/lib/python3.6/site-packages/_pytest/fixtures.py:787: in execute
    return ihook.pytest_fixture_setup(fixturedef=self, request=request)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:745: in __call__
    return self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:339: in _hookexec
    return self._inner_hookexec(hook, methods, kwargs)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:334: in <lambda>
    _MultiCall(methods, kwargs, hook.spec_opts).execute()
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:613: in execute
    return _wrapped_call(hook_impl.function(*args), self.execute)
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:254: in _wrapped_call
    return call_outcome.get_result()
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:279: in get_result
    raise ex[1].with_traceback(ex[2])
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:265: in __init__
    self.result = func()
../../anaconda3/lib/python3.6/site-packages/_pytest/vendored_packages/pluggy.py:614: in execute
    res = hook_impl.function(*args)
../../anaconda3/lib/python3.6/site-packages/_pytest/fixtures.py:818: in pytest_fixture_setup
    result = call_fixture_func(fixturefunc, request, kwargs)
../../anaconda3/lib/python3.6/site-packages/_pytest/fixtures.py:712: in call_fixture_func
    res = fixturefunc(**kwargs)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

    def get_direct_param_fixture_func(request):
>       return request.param
E       AttributeError: 'dict' object has no attribute 'param'

../../anaconda3/lib/python3.6/site-packages/_pytest/fixtures.py:247: AttributeError
================================================================================================================================================================== 85 passed, 1 error in 28.45 seconds ===================================================================================================================================================================

[The-Compiler]

This works fine for me:

import pytest

@pytest.mark.parametrize('x', [None])
@pytest.mark.parametrize('y', [None])
def test_foo(x, y):
    pass

[RonnyPfannschmidt]

what version of pytest is that? the traceback has some code that i personally got rid of a while back

[The-Compiler]

3.2.1, see the version info in the original post - but I can't reproduce it there either.

[RonnyPfannschmidt]

@The-Compiler thanks for the pointer and trying already

[andreacassioli]

Thanks all, here my findings: in the error message you can see

    def get_direct_param_fixture_func(request):
>       return request.param
E       AttributeError: 'dict' object has no attribute 'param'

Now, I have a fix a fixture in conftest.py named request as well! Apparently this generates some name shadowing and thus the error.

Renaming the fixture solve the issue. The error message was very cryptic.

[RonnyPfannschmidt]

thanks for the followup

[The-Compiler]

@andreacassioli You might want to upgrade to a newer pytest version, where this was improved (see #611/#4209).