How to detect if a field will lazyload?

I'm trying to write some database-tests (to be run in arquillian). I need to know what fields are populated and which fields that are not populated.

So I tried with detach but unfortunally it isn't specified what is going to happend with attributes, and eclipselink chooses to keep them in a lazyloading state as long as the transactions runs (or you leave the managed context).

So, my question after a couple of fails, is it possible to detect if a field (not a list) will lazyload without leaving the managed context?