Record more granular test results. #158
Description
I would like to record which tests pass and which tests fail so that it is easier to diagnose things. We may also want to output DEMs (#150) on failure. The Test Anything Protocol is a very simple way to output information from tests that can be consumed by other tools, so it might be useful to start there.
The snapshot tests already output success or failure lines, so these can be updated to use the TAP format.