I believe its more readable to define everything in the test because everything you need is there, especially in cases with many lines of code where you have to scroll up and down the file. But this is just my opinion.

Since you mentioned `self.mentor` there is a possibility that you don't need this user for each test. Although, in this case no harm can be done by this object, the argument here is that you still defining something that you don't need and in some other cases, may or may not, cause some problems. My two cents. Feel free to leave it as it is.