"Personality tests" tie into and are informed by the idea that you are at the same time a single immutable Self and that that immutable Self can be reified by the consumer market. Their ideology is at bottom marketism: clever men from the pop-psychological field of marketing have simmered all qualia of the self down to four to ten quintessences, and you can discard any aspect of the self not covered by those quintessences as extraneous. The ideology of the personality test is the ideology of the Hot Topic T-shirt rack: you are you, you are unique, but we have one of you in stock.