All of our file attachment tests were living in a single module, making

it annoying to maintain. This change splits this up into several

modules, one per class or purpose.
We did have some tests specific to the review request diff viewer

fragment code, which was living in here. These tests have moved to the

module responsible for this code's tests.
No code within the tests have changed. This means that they're largely

using older style and doc guidelines. There are currently no plans to

redo any of this.

All unit tests pass.