CODEWITHSUNDEEP
pythonpython-2.7inheritanceexceptionpytest
magnum_skrattar
magnum_skrattar

Reputation: 105

In pytest, how to assert if an exception (which is inherited from a parent exception class) is raised?

What I have done :

I have a function def get_holidays(): which raises a Timeout error. My test function test_get_holidays_raises_ioerror(): first sets requests.get.side_effect = IOError and then uses pytest.raises(IOError) to assert if that function raises an IOError.

What the issue is :

Ideally this should fail, since my actual get_holidays() does not raise an IOError. But the test passes.

Possible reason :

This might be because Timeout is inherited from the IOError class.

What I want :

Want to assert specifically if IOError is raised.

Code :

from mock import Mock
import requests
from requests import Timeout
import pytest

requests = Mock()

# Actual function to test

def get_holidays():
    try:
        r = requests.get('http://localhost/api/holidays')
        if r.status_code == 200:
            return r.json()
    except Timeout:
        raise Timeout

    return None

# Actual function that tests the above function

def test_get_holidays_raises_ioerror():
    requests.get.side_effect = IOError
    with pytest.raises(IOError):
        get_holidays()

Upvotes: 1

Views: 3348

Answers (1)

Alexander Fasching
Alexander Fasching

Reputation: 621

pytest captures the exception in an ExceptionInfo object. You can compare the exact type after the exception.

def test_get_holidays_raises_ioerror():
    requests.get.side_effect = IOError
    with pytest.raises(IOError) as excinfo:
        get_holidays()
    assert type(excinfo.value) is IOError

Upvotes: 0

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