Model pass_through

[marcfil]

@apotonick said:

This is incorrect. It is impossible that there's a test covering the new functionality introduced with that patch - otherwise this PR would be redundant. I kindly ask you guys to add a test illustrating the new functionality, it's for your best, because in one year someone might change this and no test covers it, and then we have a regression.

[marcfilipan]

find and pass_through were using the same code, yet only find was being tested on, by removing find (which was duplicate code anyway), pass_through is now sufficiently tested.