Refactor SessionsController test

This change is already merged, but I wanted to add some notes explaining some of the changes I made. Once my notes have been reviewed, this PR can be closed.
I broke this across lines to restrict the line to fewer than 80 characters.

That said there seem to be different schools of thought on whether or not this is the right thing to do. As a general rule of thumb many recommend keeping lines under 80 characters, but often to achieve this you create more vertical lines which means, vertically speaking, you see less on the screen at once.

Personally, I don't really care because I generally have my editors arranged such that lines > 80 chars are not an issue. Additionally most editors provide some functionality for viewing different regions of the same file simultaneously, so vertical spacing isn't really an issue either.

All that said, when pull requests are going through Github which is less flexible when it comes to line length, I tend toward keeping lines under 80 chars so nothing gets cut off in the pull request and everything is easily visible for review. It wasn't an issue in this case, but it provided a good time to explain my thinking.