Increase test coverage

[mschoenlaub]

Not sure where we are at, so we need to measure it. But I don't think we are anywhere near an acceptable threshold, less so for the current version of the spec.

[technicalpickles]

#59 landed, so we are collecting data now. Here's the first report with it enabled: #60 (comment)

link

At 98%, I think we are pretty good. I'm more inclined to worry about the level of coverage when more of the spec is implemented rather worry too much right now.