We can't be sure that crap raws aren't used for brewing, simply based off testing of raws. Whether those raws are even used for brewing is a question itself.
A better test (i would think) is to GCMS the oil. We can't be sure if crap raws are used, but in the event they were used, at least we know that there is nothing toxic (that is volatile) from those impurities, in the oil. If the GCMS shows the use of high amounts of solvents, then I'd be suspicious of the raw purity as well.
The closest we can get, to tieing the raws to the oils, is to GCMS both of them. If you see weird stuff in the oils but not the raws, then clearly something must have happened along the way, or a different set of raws are used. Practically speaking, this will not happen as no vendor will pay for this just to hold themself accountable.