IndexError occurs if pytest.mark.parametrize is used with keyword arguments.

[KillAChicken]

Description
The names of the arguments for parametrization are determined only by positional arguments of pytest.mark.parametrize. It leads to the IndexError in the following code.

import pytest


@pytest.fixture(params=range(1))
def parametrized_fixture(request):
    return request.param


@pytest.mark.parametrize(argnames="parametrized_argument", argvalues=range(1))
def test_parametrization(parametrized_fixture, parametrized_argument):
    pass

while the tests with positional arguments work fine

import pytest


@pytest.fixture(params=range(1))
def parametrized_fixture(request):
    return request.param


@pytest.mark.parametrize("parametrized_argument", argvalues=range(1))
def test_parametrization(parametrized_fixture, parametrized_argument):
    pass

The issue is reproducible only with invokation of the pytest_generate_tests, thus parametrization works in case, when all the fixtures are parametrized by pytest.mark.parametrize decorator:

import pytest


@pytest.mark.parametrize(argnames="parametrized_argument", argvalues=range(1))
def test_parametrization(parametrized_argument):
    pass

Environment:
py (1.4.34)
pytest (3.2.3)

[RonnyPfannschmidt]

this will be fixed by #2819 thanks to @leezu

[RonnyPfannschmidt]

i just merged that one, the next feature/patch release will include it