Python unittest: How to raise IndexError for sys.argv?-CodePudding

I am trying to test the case where the number of parameters in the script being executed is less than three. When debugging, I see that an IndexError occurs, but for some reason assertRaises does not "see" it. Can anyone help fix this?

my_file.py:


def my_func():
    try:
        sys.argv[2]
    except IndexError:
        pass

text_sys_srgv.py

import sys
import unittest
import my_file
from unittest.mock import patch

class TestServer(unittest.TestCase):
    def test_my_func(self):
        work_dir = os.path.dirname(os.getcwd())
        my_file_full_path = os.path.join(work_dir, 'my_file.py')

        test_args = [my_file_full_path, 'arg1']
        with patch.object(sys, 'argv', test_args):
            self.assertRaises(IndexError, my_file.my_func)

if __name__ == '__main__':
    unittest.main()

CodePudding user response：

Your my_func does not raise the exception. It catches it. assertRaises will confirm if the exception is actually thrown out of the function, instead of caught inside it and suppressed.