Patch over a Function Imported Inside Another Function
In Order to Avoid a Circular Import, I've Been Forced to Define a Function That Looks Like: # Do_Something. Py Def Do_It(): From. Helpers Import Do_It_Helper #...
In order to avoid a circular import, I've been forced to define a function that looks like:
# do_something.py
def do_it():
from .helpers import do_it_helper
# do stuff
Now I'd like to be able to test this function, with do_it_helper patched over. If the import were a top level import,
class Test_do_it(unittest.TestCase):
def test_do_it(self):
with patch('do_something.do_it_helper') as helper_mock:
helper_mock.return_value = 12
# test things
would work fine. However, the code above gives me:
AttributeError: <module 'do_something'> does not have the attribute 'do_it_helper'
On a whim, I also tried changing the patch statement to:
with patch('do_something.do_it.do_it_helper') as helper_mock:
But that produced a similar error. Is there any way to mock this function, given the fact that I'm forced into importing it within the function where it's used?
1 Answer
You should mock out helpers.do_it_helper:
class Test_do_it(unittest.TestCase):
def test_do_it(self):
with patch('helpers.do_it_helper') as helper_mock:
helper_mock.return_value = 12
# test things
Here's an example using mock on os.getcwd():
import unittest
from mock import patch
def get_cwd():
from os import getcwd
return getcwd()
class MyTestCase(unittest.TestCase):
@patch('os.getcwd')
def test_mocked(self, mock_function):
mock_function.return_value = 'test'
self.assertEqual(get_cwd(), 'test')
Hope that helps.
Sarah Jenkins is a veteran tech journalist with over 12 years of experience covering artificial intelligence, mobile innovations, and digital ethics. Her insights have appeared in leading technology publications worldwide.
