python - Use `unittest` to verify that the `exit` function was called -

i defined simple configuration manager (parses config files , verifies keys exist in them) , i'm writing tests it.

in many cases config file is invalid, want configuration handler call exit(). there way can write tests ensure exit called , still continue testing? can perhaps, testing environment only, "mock" exit function?

i using python 2.7 , unittest.

sys.exit() raises systemexit exception, should caught unittest framework. can check systemexit raised test cases.

example, exit_test.py:

import sys import unittest   def func():     sys.exit()   class mytest(unittest.testcase):      def test_func(self):         self.assertraises(systemexit, func)   if __name__ == "__main__":     unittest.main() 

run:

$ python exit_test.py  . ---------------------------------------------------------------------- ran 1 test in 0.000s  ok