How to test that a function is called within a function with nosetests

Question

I\'m trying to set up some automatic unit testing for a project. I have some functions which, as a side effect occasionally call another function. I want to write a unit test wh

Answer 1

You can mock the function b using mock module and check if it was called. Here's an example:

import unittest
from mock import patch


def a(n):
    if n > 10:
        b()

def b():
    print "test"


class MyTestCase(unittest.TestCase):
    @patch('__main__.b')
    def test_b_called(self, mock):
        a(11)
        self.assertTrue(mock.called)

    @patch('__main__.b')
    def test_b_not_called(self, mock):
        a(10)
        self.assertFalse(mock.called)

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

Also see:

• Assert that a method was called in a Python unit test
• Mocking a class: Mock() or patch()?

Hope that helps.