Then we get the Sorting Hat moment. No, we mean, then we get the aptitude test to see what faction each person belongs in. Actually, the aptitude test isn't like Harry Potter's Sorting Hat because the aptitude test only tells you what faction you'd best fit. But then the "choice" is still yours—you can take the advice of the aptitude test or not.
The tests are private, so no one gets to see how you do; and also secret, in that you don't start sharing your results right after. (Not like usual tests, then.)
Beatrice nervously waits for her turn. Though she was born into an Abnegation family, she doesn't feel that she totally belongs.
Beatrice meets Tori from Dauntless, who will run the aptitude test on her.
The test goes on in a virtual reality where Beatrice faces several challenges, each of which has a few solutions.
For instance, she faces a dangerous dog: does she try to make friends by giving it cheese (which will not be good for whoever has to clean up after the dog later), does she attack it with a knife, or does she show her book-learning by playing submissive so it won't attack her?
So she goes through a series of challenges and discovers that she is… (please turn to Chapter 3).