Test task with InputChanges

Short answer - consider this more of an integration test.
Long answer -basically I have a multi-build project that creates some Plugins, and then in a subproject I want to use those plugins. I can do it with composite builds, but it’s a lot messier than I’d like.
Ideally I’d be able to have this sub-project use the plugins project as a build dependency, but I can’t. I can use it as a regular dependency though, I just don’t have a way to specify input changes. (I don’t care if it’s not actually incremental)