That would be VI. A test relies on the honesty and self-awareneness of the taker, same with a questionnaire (although tests are a bit better), but VI; VI doesn't lie. If your pattern recognition database is correct, you can see what type people are just by looking at them. Somebody could be asserting that they are an IEE-Fi all day long, but if you see them and notice that they're an LSI-Ti instead, there's no possible deception. Then it can be confirmed via observing a bit more if it seems correct (their interaction) and that's it. No ruse would be efective. You just gotta be able to call an ace an ace and a spade a spade.
The only problem is getting sufficiently good at it.