I'm trying my best to learn how to properly test my Android apps. Now I usually use the following structure:

* Model
* Retrofit (letting it handle the threading by using callbacks)
* Wrapper for retrofit calls that posts events on success and failure
to be picked up by presenters.
* Presenters.
* Views.

I've tested apps before where I handled the threading myself. In this case I have no idea on how to verify if my wrapper is actually calling event posting methods because those methods are called on callbacks. What can I do to solve this problem?

The only solution I can come up with is not using the callbacks, but they are SO convenient. Isn't it a step back to handle things myself just for the sake of testing?

I can only guess my ways of architecting this are poor for testing.

EDIT: This question suggests that it's a good idea to split the testing as: 

> 
> 1.- Test that your async process is submitted properly. You can mock the object that accepts your async requests and make sure that the submitted job has correct properties, etc.
>  2.- Test that your async callbacks are doing the right things. Here you can mock out the originally submitted job and assume it's initialized properly and verify that your callbacks are correct.
> 
> 
> 

But how can I test the first part without mocking the Retrofit service (because one should never mock third party code)?