I really need to go back to other work priorities, so I won't have time to write tests for awhile. I would love some help if anyone has time to spare.
I didn't feel I could write tests while I was exploring and thrashing around to figure out what all the plugin needed to do. I focused on the UX and writing extensive help_texts for each field/target to make sure using them made sense (answering questions like: should this be a field? Should it be a target? Should it be inferred somehow?)
Now, however, I think the plugin is conceptually complete. So, writing tests to safeguard it for future refactors and changes makes a lot of sense. I'm sad I ran out of time to do this right now though 😞. I really want to get it into pants.