Fix typo in test.yml

[jonasfj]

Couldn't get the tests to run, so I just assumed it was a fluke. Only when I landed on master it was obvious that I had malformed YAML :see_no_evil:

[jonasfj]

88.7% coverage is not bad!

Not bad at all.

I'm not actually sure we'll get much more coverage by collecting coverage from integration tests, etc.

We have:

• Error cases that are not covered by testing -- this is probably worth returning to, once refactoring is done.
• Unused functions, mostly harmless toString implementations, maybe some of them can go away. But let's review later.

Code coverage around 80% is really good. If eventually we can cover most of the error cases, I think we should be very happy.

Let's not focus too much on the number, and focus more on what code paths are uncovered. (once we're done refactoring)