The Hug Test
Step Back and Read Her Body Language
The next time you meet her, open your arms out to hug her and motion for her to do the same.
As you embrace, give her a light peck on the lips (or the cheek if you're not feeling at the top of your game, but the lips is exponentially more revealing).
Then step back and read her body language. If she smiles at you at any point within 20 seconds of the peck, then BAM!!! you've got her!
For more info on reading body language see Attract Women with Body Language and Nonverbal Communication
For more info on testing see A Woman Will Test You — How to Pass Her Tests