AUTO cases in conftest: AssertionError

[michele-riva]

Thanks for the great work! I just stumbled across a corner case.

Example to reproduce:

conftest.py

from pytest_cases import fixture, parametrize_with_cases

@fixture
@parametrize_with_cases('arg')
def auto_cases(arg):
    return arg

test_cases.py

def case():
    return 1

test.py

def test(auto_cases):
    assert auto_cases == 1

Gives

ImportError while loading conftest
pytest_cases/common_pytest.py:925: in apply
    return apply_decorator(test_or_fixture_func, container)
pytest_cases/case_parametrizer_new.py:143: in _apply_parametrization
    cases_funs = get_all_cases(f, cases=cases, prefix=prefix, glob=glob, has_tag=has_tag, filter=filter)
pytest_cases/case_parametrizer_new.py:303: in get_all_cases
    c = import_default_cases_module(caller_module_name)
pytest_cases/case_parametrizer_new.py:670: in import_default_cases_module
    assert parts[-1][0:5] == 'test_'
E   AssertionError: assert 'conft' == 'test_'

Seems very reasonable to me to not allow AUTO use in a conftest.py as it can be ambiguous which cases are to be used for parametrization. However, it probably would be nicer to explicitly check for this and raise a clearer exception? E.g., at the beginning of

python-pytest-cases/src/pytest_cases/case_parametrizer_new.py

Line 650 in ab3b719

def import_default_cases_module(test_module_name):

As a side note, I realized a possible inconsistency in the doc of the @parametrize_with_cases API: it looks like the "second alternative" for looking up cases in AUTO mode is cases_<name>.py (plural), and not case_<name>.py. See

python-pytest-cases/src/pytest_cases/case_parametrizer_new.py

Line 671 in ab3b719

cases_module_name2 = "%s.cases_%s" % ('.'.join(parts[:-1]), parts[-1][5:])

[smarie]

Thanks @michele-riva ! Indeed I confirm

• The docstring and API reference page state By default (cases=AUTO) the list of test cases is automatically drawn from the python module file named test_<name>_cases.py or if not found, case_<name>.py, where test_<name> is the current module name. while the correct alternate pattern is cases_<name>.py. Note that a few comments here and there in the code have to be fixed too as they mention 'case_'.
• It would be beneficial to raise an explicit ValueError in get_all_cases just before import_default_cases_module is called (here) if test_module_name.split('.')[-1] does not start with test_, stating that AUTO is not allowed outside of normal test files.

Would you like to propose a PR for these two mods ?

[michele-riva]

Sure, I can draft one right away.

[michele-riva]

Fixed by PR #320