Bug in _pytest.compat.getfuncargnames() corrupts fixture handling for test methods w/ positional-only self parameter #13376
Description
- a detailed description of the bug or problem you are having
- Doesn't depend on specific packages [ ] output of
pip listfrom the virtual environment you are using - Isn't related to specific Pytest versions [ ] pytest and operating system versions
- minimal example if possible
Basic example
Passing:
import pytest
@pytest.fixture
def value_fixture():
return 'value'
class TestClass:
def test_value(self, value_fixture):
assert value_fixture == 'value'Failing:
import pytest
@pytest.fixture
def value_fixture():
return 'value'
class TestClass:
def test_value(self, /, value_fixture):
assert value_fixture == 'value'- Result:
pyfuncitem = <Function test_value>
@hookimpl(trylast=True)
def pytest_pyfunc_call(pyfuncitem: Function) -> object | None:
testfunction = pyfuncitem.obj
if is_async_function(testfunction):
async_fail(pyfuncitem.nodeid)
funcargs = pyfuncitem.funcargs
testargs = {arg: funcargs[arg] for arg in pyfuncitem._fixtureinfo.argnames}
> result = testfunction(**testargs)
^^^^^^^^^^^^^^^^^^^^^^^^
E TypeError: TestClass.test_value() missing 1 required positional argument: 'value_fixture'Reason
_pytest.compat.getfuncargnames() collects keyword-callable parameters as fixture-receiving arguments:
Lines 134 to 142 in 103b2b6
Then it removes the first one – supposedly 'self' – if given function is a non-static method:
Lines 149 to 157 in 103b2b6
Yet, if 'self' is defined as positional only, it wasn't contained in arg_names before removal ...