patch_example.py

"""A simple example of using unittest.mock to patch a function in a test"""

import unittest
from unittest.mock import patch

def f(x):
    return 2**x
  
def g(y):
    retrun f(y % 15)
  
class SimpleTest(unittest.TestCase):
  
    @patch('__main__.f')    # Only works if running directly; __main__ should be package name
    def test_f_and_g(self, mock_f):
        mock_f.return_value = 4     # When f() runs during the test, it will always return 4
        self.assertEqual(4, g(50))
        

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

requests_patch_example.py

"""A less trivial example of using patching for HTTP requests"""

import unittest, requests
from unittest.mock import patch

def connect(url):
    response = requests.get(url)
    
    if response.ok:
        return 'Connection successful'
    else:
        return 'There was an error connecting'
        

class ConnectionTest(unittest.TestCase):
    @patch('requests.get')
    def test_good_connection(self, mock_response):
        mock_respone = MockRespone(ok=True)
        assertTrue('success' in connect('myawesomesi.te').lower())
        
    @patch('requests.get')
    def test_bad_connection(self, mock_response):
        mock_response = MockResponse(ok=False)
        assertTrue('error' in connect('notaweso.me').lower())
        

class MockRepsone(object):
    def __init__(self, *args, **kwargs):
        self.ok = kwargs.get('ok', True)
        

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