Shit test = flirting
If a girl is shit testing you it means she's considering sleeping with you but wants to make sure you are the "right guy". There really isn't one way to pass a shit test and it's very contextual like
@ulrich said
But a trick to get the answer she wants to hear is to give a blank expression and look away to divert your attention to something else. Usually when you do this she will try and get your attention back and also answer the shit test for you
Example
Girl: "Do you do this with all the girls?"
Me: *Bored Expression* ... then look away
Girl: "I knew it, you're a total player aren't you"
Me: *Bored Expression*
Girl: "You players are all the same"
Me: "If you say so, but hey you never finished telling me about that fight you had with your grandma"
It's a low effort way of handling shit tests but also helps you because you remain vague and ambiguous. Giving her no logical reason to reject you and give you a nice boost in tension and wiggle room to continue the seduction