Tests for rendered output

[Mr0grog]

We really need to test that the rendered output is correct if we want to do further work. This is an attempt to get that started.

This is a work in progress—we should get evolve a little bit of a nice structure for making these tests easier here before merging into master.

[bensheldon]

👍 Goes great with #73

[bensheldon]

@Mr0grog we have a merge conflict, but I think the basic functionality here adds value in its current state, even if it's not the cleanest interface. Could you please try to clean up the the conflict and we'll merge this.

[Mr0grog]

Wow, I remember the alst time I looked at this code and that was a long time ago! Will see if I can make sure this is all still good to go soon. Probably a lot of old dependencies that should be updated, too :\

[bensheldon]

One thing at a time :-) I'd rather have this code merged and working with existing/old dependencies than broken with new ones :-)

[Mr0grog]

Oh, was not implying that that should happen on this branch. Just saying. Everything in this repo is basically two years out of date.

[coveralls]

Coverage increased (+7.76%) to 26.11% when pulling 0a0819e on bug-10-image-tests into 70a6913 on master.

[Mr0grog]

Woo, and dramatically increased coverage to boot. Merging.