If you aren't quite ready to ditch callbacks but are looking for a tool to help you untangle gnarly models or at least update your tests to prevent more complexity from being added you might want to check out this gem I built for GitHub a few years ago (can't provide full link since I'm a new user to this platform but look up this on github): jonmagic/arca
We still use it in our test suite today to warn folks if they are about to introduce something that is considered more complex than we want to support.