How to check of exceptions in nested functions when using MagicMock objects in Pytest?

I've a function (myfunc), with a validation input a and and c credentials that will setup a service to call func_z.

For some validation input, func_z will throw an error, and in other cases, it'll return some dictionary of values. And I've an outer_func that modifies the output of func_z:

class XError(Excception):
    pass

def myfunc(a, b, c):
    x = c.setup_client('x')
    try:
        x.func_z(a) # Check if x.func_z(a) works proper
    except:
        raise XError
    
    return b**2


def outer_func(a, b, c):
    return myfunc(a, b, c) + 1

When testing the function, I had to mock the c credentials. So I tried to test with:

import pytest
from unittest.mock import MagicMock


test_data = ( (('fr', 5), 26), ('de', 7, 50), (('zh', 5), XError) )

SIDE_EFFECTS = {'fr': {'status': 'okay'}, 'de': {'status': 'okay'}, 'zh': XError}

@pytest.mark.parametrize("a, b", test_data)
def mytest(a, b, expected):
    mock_creds = MagicMock()
    mock_service = MagicMock()
    mock_creds.setup_client.return_value = mock_service
    mock_service.func_z.return_value = SIDE_EFFECTS[a]
    
    assert outer_func(a, b, c) == expected
    

Somehow the XError didn't get raised in the pytest and the output returns 26 for ('zh', 5) inputs instead of XError.

Did I use the return value in the mock objects wrongly?

Is it possible to allow and check for raised error or outputs with mock objects in pytest?