Some tools (notably Checkstyle and Rubocop) have default rules that

check the name of the file being passed to it, ensuring they meet

requirements. Given that we're passing tempfiles with auto-generated

filenames, these tests were guaranteed to fail. We were able to disable

this for Rubocop, but this was a far more annoying procedure for

Checkstyle.
To address this now and going forward, we now generate a temp directory

and place the file inside of it, preserving the original name.
This is largely transparent to tool implementations, with the exception

of Rubocop, which no longer needed the filename rule suppressed. It does

impact nearly all unit tests, as those check the command being run, but

otherwise there's no impact.

Unit tests pass on Python 2.7 and 3.x.