Create a parametrized fixture

[Gadzillion]

I want to create a parametrized fixture that gets args (for example two lists) from a test, performs some actions on it, return one list (based on two given), and uses one value at a time from the list (code below doesn't work, but it shows my idea):

LIST_1 = [1, 3]
LIST_2 = [1, 2]

@pytest.fixture(scope="function", params=[request])
def tester(request):
    some_actions ...
    [I for I in request.param[0] if I not in request.param[1]]
    return ... (return one value at a time (like request.param). for example (1, 1) , then (3, 2))

@pytest.mark.parametrize('tester', [(LSIT_1, LIST_2)], indirect=True)
def test_button(tester):
    ...

[The-Compiler]

I don't think you can do this directly from a fixture. You could either use parametrize and some helper function:

import pytest

LIST_1 = [1, 3]
LIST_2 = [1, 2]

def gen_params(elems1, elems2):
    return list(zip(elems1, elems2))

@pytest.mark.parametrize('tester', gen_params(LIST_1, LIST_2))
def test_button(tester):
    assert False, tester

or use a custom mark and the pytest_generate_tests hook with Metafunc.parametrize to implement custom parametrization.

If you can say more about what your actual use-case is, it might be possible to suggest a simpler/better alternative as well.

[Gadzillion]

thx u)