Run functional test in CI #68

The CI runs the unit tests, but not the functional test. It should probably also run the functional.

Proposed enhancement

Add the running of the functional test as a job in the "main" workflow; it will require the build job but that should be it.

Alternatives

• Do nothing. There are things that are caught in the functional which aren't in the unit tests.
• Improve the unit tests instead, so the functional doesn't catch anything that the unit tests don't. Long-term I'd like to do this but short-term it'll help us find things (in particular, helps to be concrete about what might have to go into the unit tests.)

Closure condition

This issue should be closed when a PR is merged that adds the functional as a job in the CI main workflow.