Here are some open source tools which can help you do everything as you want:
- OCMockito - https://github.com/jonreid/OCMockito
It's easy to mock any object, protocol can also be mocked, but can't handle the async methods. - Expecta - https://github.com/specta/expecta
It provides powerful matchers and easy to use. - Aspects - https://github.com/steipete/Aspects
Just like the name, you can do something before or after the methods or replace the methods' implementation. - Kiwi - https://github.com/kiwi-bdd/Kiwi
It's very very powful to do asynchronous testing, stub methods to capture any methods' parameter, protocol mock and handle any you want to do.
Kiwi docs - https://github.com/kiwi-bdd/Kiwi/wiki
