Some tests are flaky

[jackjohn7]

I've never produced these errors locally, but I've seen them appear several times in CI. I'm not sure what's causing it yet.

Missing Table

Incorrect score computation

Malformed database file (seems to occur more frequently on Blacksmith runners)

[funnyboy-roks]

This feels like two tests are trying to write to the same database file. This could be the case if the paths generated by async_tempfile are not random enough (or based on time or something like that). They don't use create_new so we won't get an error if there is already a file there.
By default, the name they generate is a random string, but I enabled the uuid feature (which uses a uuid) in #53, so we'll see if that changes anything.