Snapshot tests?

[jbrown215]

We should probably be recording tests of some sort. A way to do this is to have an input and expected output and run diff on the expected vs actual output. Snapshot tests are somewhat annoying because they need to be re-recorded whenever the output style changes.

@jluningp, if you know of a better way to test than snapshots for this kind of thing, I'm happy to go into that. Otherwise, I'll try to figure out how to integrate snapshot tests + stack and I'll write a script to re-record all tests so that it doesn't get too annoying as we make changes.