The talk about my personal journey of using mocks in tests. Why I personally don’t like them? Why it’s kind of a hot topic in the dev communities?

1. Some strange stories about
mocks
And why we don’t like them?

2. Andrew
Nashkolniy
Matic Insurance

3. Story #1: The Prehistory

8. Story #2: Testing with mocks

10. With Mocks Pros:
- Isolation.

11. With Mocks Pros:
- Isolation.
- Speed.

12. With Mocks Pros:
- Isolation.
- Speed.
- Accuracy.

14. With Mocks Cons:
- Avoided Contracts.

15. With Mocks Cons:
- Avoided Contracts.
- Rely on Integrations.

16. With Mocks Cons:
- Avoided Contracts.
- Rely on Integrations.
- Hard Refactoring.

17. Story #3: Testing without mocks

18. Without Mocks Pros:
- Refactoring.

19. Without Mocks Pros:
- Refactoring.
- Reliability.

20. Without Mocks Cons:
- Longer runtime.

21. Without Mocks Cons:
- Longer runtime.
- Snowball effect.

22. Without Mocks Cons:
- Longer runtime.
- Snowball effect.
- You still use mocks.

24. Story #4: Origins

25. Problems with mocks in Java:
- Other classes side effects.

26. Problems with mocks in Ruby:
- Weak input params checks.
- No output params checks.
- Other classes side effects.

27. Interfaces
&
Strong typing

28. Unacceptable problems:
- Refactoring difficulties.

29. Unacceptable problems:
- Refactoring difficulties.
- Unreliable tests.

31. No mocks by default. But...

32. Good usage mocks:
- Networking.
- Streams.
- IO operations.
- Time.
- System calls.

33. In the very end it really depends

34. Materials:
- https://www.youtube.com/watch?v=KYG5C1CEkOk
- https://medium.com/javascript-scene/mocking-is-a-code-smell-944a70
c90a6a
- https://blog.codecentric.de/en/2018/03/mock-what-when-how
- https://blog.carbonfive.com/2011/02/11/better-mocking-in-ruby
- https://www.solutionsiq.com/resource/blog-post/to-mock-or-not-to-mock-is-that-even-a-question
- https://clean-swift.com/to-mock-or-not-to-mock
- https://blog.codecentric.de/en/2017/07/mocks-real-thing-tips-better-unit-testing
- https://dev.to/asizikov/you-are-mocking-it-wrong-5gh3
- https://www.swiftbysundell.com/posts/mock-free-unit-tests-in-swift
- https://semaphoreci.com/community/tutorials/mocking-with-rspec-doubles-and-expectations
- https://tomassetti.me/mocking-in-java-why-mocking-why-not-mocking-mocking-also-those-awful-private-static-methods
- https://softwareengineering.stackexchange.com/questions/363112/is-it-really-a-bad-practice-to-mock-a-pojo-value-object-if-you-dont-care-ab
ou
- https://stackoverflow.com/questions/6875173/to-mock-or-not-to-mock
- ...

35. Thank you!