Summary - Mocking
- Python course
- Advanced
- Lesson 24/83
- 5 min
Combine Mock, patch and side_effect to write a service test.
Summary - Mocking
This group covered the tools of unittest.mock. Mock produces fakes; patch swaps a real object during a test; MagicMock supports magic methods; side_effect gives sequential or exceptional behavior; assert_called_with checks calls.
The final task combines Mock, side_effect and assert_called_with: you'll build a fake service method that returns sequential responses and check the calls.
Practice Mock + side_effect + assert combined
Import Mock from unittest.mock. Create m = Mock(); set m.side_effect = [10, 20]. Print m() and m(). Add the check m.assert_called(); print print("ok").
Starter code
# import Mock from unittest.mock
# create Mock m; set side_effect [10, 20]
# print m() twice
# assert_called check and print "ok"Sample solution
from unittest.mock import Mock
m = Mock()
m.side_effect = [10, 20]
print(m())
print(m())
m.assert_called()
print("ok")Expected output
10 20 ok
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What do you use for a Mock that returns different values in sequence?
- side_effect Correct answer
- MagicMock
- return_value
- patch
Explanation: side_effect cycles a list or calls a function.
2 Summary: call check
m = Mock()
m(7)
m.____(7)m = Mock()
m(7)
m.assert_called_with(7)Explanation: m.assert_called_with(7) checks the call argument.
3 Match the group tools
| Term | Meaning |
|---|---|
Mock |
Fake object |
patch |
Swaps real |
MagicMock |
Magic methods |
side_effect |
Sequential/exception |