Multiple param values in fixture

[DavideCanton]

Hi all, I've noticed a not very well documented behavior in parametrizing fixtures.

A fixture with params errors out in the discovery if the params have multiple values. I believe it's because a single name fixture cannot bind different parameter values, but I didn't find anything about it in the docs, neither the error is clear:

import pytest


@pytest.fixture(params=[pytest.param(i, 5) for i in range(5)])
def my_fixture(request):
    return request.param


def test_foo(my_fixture):
    assert my_fixture in {1, 2, 3, 4, 5}

$ pytest tests/foo_test.py

# removed output for brevity

tests/foo_test.py::test_foo: in "parametrize" the number of names (1):
  ['my_fixture']
must be equal to the number of values (2):
  (0, 5)

# removed output for brevity