I am lately been asked the question what test is performed on olive oil to confirm it is extra virgin olive oil a lot so I will try to give a quick answer here.
A producer will take a sample to a chemical lab to verify the purity and the acidity of the oil and have it tested by a panel to verify that its aromas and taste meets the standards.
Now if I buy a EVOO lets say from a supermarket there is no chance I can verify it is indeed EVOO.Why is that? It is because oils can be neutralised to have no taste at all and then have some olive added to it to give it the taste and colour.
The best way to be sure? Produce your own, that's the best. If that is not possible the second best is to buy from a small producer of olive oil and here in the UK we have many choices nowadays. Of course I don't know what everybody sells but I give zero chances that a small producer would ever cheat, frankly there in no reason to do so.