How to get around “sys.exit()” in python nosetest?

问题

It seems that python nosetest will quit when encountered "sys.exit()", and mocking of this built-in doesn't work. Thanks for suggestions.

回答1:

You can try catching the SystemExit exception. It is raised when someone calls sys.exit().

with self.assertRaises(SystemExit):
  myFunctionThatSometimesCallsSysExit()

回答2:

import sys
sys.exit = lambda *x: None

Keep in mind that programs may reasonably expect not to continue after sys.exit(), so patching it out might not actually help...

回答3:

If you're using mock to patch sys.exit, you may be patching it incorrectly.

This small test works fine for me:

import sys
from mock import patch

def myfunction():
    sys.exit(1)

def test_myfunction():
    with patch('foo.sys.exit') as exit_mock:
        myfunction()
        assert exit_mock.called

invoked with:

nosetests foo.py

outputs:

.
----------------------------------------------------------------------
Ran 1 test in 0.001s

OK

回答4:

This is an example in the unittest framework.

with self.assertRaises(SystemExit) as cm:
    my_function_that_uses_sys_exit()
self.assertEqual(cm.exception.code, expected_return_code)

来源：https://stackoverflow.com/questions/8332090/how-to-get-around-sys-exit-in-python-nosetest