I think that what's said here applies not only to personality tests, but to personality typing in general. I notice that a lot of times, people seem to try and act like their personality type, rather than being themselves; you simply cannot expect every ENFp to always be feeling and never be logical. That's why it's a mistake to say that one is or is not a specific type based on one piece of evidence. As I said before, you have to look at the whole picture. And that follows from the fact that the article is right in saying that people are usually a number of types, not just one single type (although one type might predominate).