cannot decorate @pytest.mark.usefixtures("xy") onto class inherits from unittest.TestCase

[willhyper]

minimum example:

import unittest
import pytest

xy1 = (1, 2)
xy2 = (3, 4)


@pytest.fixture(scope="class", params=[xy1, xy2])
def xy(request):
    request.cls.x, request.cls.y = request.param


@pytest.mark.usefixtures("xy")
class TestClassTestCase(unittest.TestCase): # Failed: The requested fixture has no parameter defined for the current test.
    def test_method1(self):
        print('access fixture attributes', self.x, self.y)


@pytest.mark.usefixtures("xy")
class TestClassObject(object): # ok!
    def test_method1(self):
        print('access fixture attributes', self.x, self.y)

motivation of such example:

pytest allows @pytest.mark.parametrize decorated on test functions on module level. One could have developed tests as

import pytest

xy1 = (1, 2)
xy2 = (3, 4)
xy = [xy1, xy2]

@pytest.mark.parametrize('x,y', xy)
def test_fixture(x, y):
    print('access fixture attributes', x, y)

my incentive on applying fixture onto class level is to leverage predefined test methods in super class, such as assertRaises in unittest.TestClass. if @pytest.mark.usefixtures cannot decorate on general classes, the use of it is less obvious, as @pytest.mark.parametrize functions the same and easier to write.

[RonnyPfannschmidt]

parametrization is not supported for unittest tests

btw, this is a duplicate issue i will find the original one later

[pytestbot]

GitMate.io thinks possibly related issues are #541 (Can't use pytest.mark.parametrize inside unittest class), #378 (@pytest.mark.usefixtures take no effects on fixtures), #1464 (pytest.mark on TestCase affects base classes), #3308 (Question: Can someone explain the below uses of @pytest.mark.usefixtures), and #2806 (mark.usefixtures registered fixtures of all test class subclasses invoked despite -k).

[RonnyPfannschmidt]

oh - gitmate already did - the issue is #541

[willhyper]

Thanks @RonnyPfannschmidt !
Do you mind elaborating "parametrization is not supported for unittest tests"?
Shall I understand it as my use case is not supported? or, my use case is not valid so no support?

Also I don't think #541 is a duplication. Here is the reason:
#541 decorates @pytest.mark.parametrize on class method(s). Only methods got decorated are affected. #541 anyway is a dead end because the first argument in every class method is "self", which cannot be parameterized.
Here I decorate @pytest.mark.usefixtures on class itself, which propagates fixtures to all methods in the class.

[RonnyPfannschmidt]

the use case is invalid - parametrized fixtures and tests do not support unittest - and will never support unittest

parameterize and fixtures with params are only availiable to native pytest tests

[RonnyPfannschmidt]

also #541 applies since both parameterize and fixture(param=...) use the same mechanism

[willhyper]

Agh, got it. Thanks for clarifying. You the best!