Gents,
I know this is an incredibly common test, so hopefully everyone has some knowledge or experience with how to deal with the "I have a boyfriend test" once your interaction with a girl is already on.
Here's the situation for context...
I picked up a 10 a few nights ago in a club with raw physical game, followed with text game and had her on a string where she responds to my texts within seconds. This 10 was literally looking around a different venue for me the next night when I wasn't even there

(she thought I might have been, but the key is that she was pursuing me).
Today I texted an invitation to meet saying "I'm going to so and so for a drink...join me". She responds quickly saying she can't today, then a minute later she texts haha and her boyfriend would kill her.
This is clearly a test. I'm relatively new at this and haven't learned yet how to break this kind of test. I'm assuming there is a tried and true method?