How to concatenate several parametrized fixtures into a new fixture in py.test?

Question

If I have two parametrized fixtures, how can I create a single test function that is called first with the instances of one fixture and then with the instances of the other

Answer 1

It is not beautiful, but may be today you know the better way.

Request object inside 'all' fixture know only about own params: 'lower', 'upper'. One way using fixtures from a fixture function.

import pytest

@pytest.fixture(params=[1, 2, 3])
def lower(request):
    return "i" * request.param

@pytest.fixture(params=[1, 2])
def upper(request):
    return "I" * request.param

@pytest.fixture(params=['lower', 'upper'])
def all(request, lower, upper):
    if request.param == 'lower':
        return lower
    else:
        return upper

def test_all(all):
    assert 0, all