All of you are assuming she will not misunderstand his story and immediately figure out he's mister tester. C'mon guys, this isn't your first rodeo, there's like a 50% chance she's going to somehow completely assume something else.
Also, I'm glad if she does correctly understand and lesbian girl is BTFO'd; I've been consistently pissed off at her (lesbian girl) for withholding this important information from her friend. She proclaims that he is her love rival, meanwhile selectively withholding this VERY important information from someone she supposedly cares deeply for, information which WOULD actually make him love rival rather than keeping him out of the competition.
I honestly hope that FML hates her for a while for doing this, because it really is scummy behaviour, and it's another example of a lesbian character acting terribly to get laid - when a male character acting similarly would be (deservedly) absolutely destroyed.