PyCharm throws "AttributeError: 'module' object has no attribute" when running tests for no reason
Given all the others paths were already covered:

Import order
Virtual Env created
Project's Interpreter using the Virtual Env

The only thing that occurred to me was do run the following command within the vurtal env:
pip install -r requirements.txt
And it worked! In the end, someone had updated the requirements which weren't being met by my current virtual env. Screwing up with the paths/imports within PyCharm.
So, I have a Django-REST Framework project and one day it simply ceased being able to run the tests within PyCharm.
From the command line I can run them both using paver or the manage.py directly.
There was a time when that would happen when we didn't import the class' superclass at the top of the file, but that's not the case.
We have a virtualenv set locally and run the server from a vagrant box. I assured the virtual environment is loaded and that the project's Interpreter is using the afore mentioned virtual env.
No clue on what's the matter.