actions have few tests / no real test coverage

We have no method or strategy around writing tests for our actions, which I see as a pretty major code quality problem on the client. This meta issue is meant for feedback & further issue decomposition.

The seismic refactors we've undergone is probably somewhat the cause (at least the cause of not pursuing test coverage here), but at this point, given that we are not likely to refactor the entire code base any further for the foreseeable future, we can do better here.

The issue names no files, tests, or action entry points. Start by mapping the client actions and existing test coverage, then use the findings to propose focused follow-up issues; done means an agreed testing strategy and decomposed, actionable work.

Written by the indexing model from the issue text.