It is probably a shit test, tho she doesnt want to be "sluty" since she actually does have a boyfriend.
You can neg her with something like... "ohh i asked kuz i was already sure you will come since you promised, but never mind" (she will end up like a person who doesnt keep promises). And just change the subject like you dont give a shit.
Play it cool, next time talk more to other women next to her...
You can even play it smart with some story telling how you care much about loyalty, truth etc.. (she will connect 2 + 2 lol). She will try to qualify too, but it will be hard kuz she already fucked up in that field

. So next time when you call her, she will try to make it up to you somehow

.