I am going to have to agree with most of the others, except for one minor detail. If you really do care for this girl, love her even, then make this clear to her. You want her to be happy, and you'd do almost anything for her, but that you refuse to be walked on, or taken advatage of. This will serve two purposes:
1) Let her know exactly how you feel
2)Also remove any doubt in her mind of your willingness to lay down to play door mat.
Most likely though, more than she is testing you, she is testing herself. She needs to find out what she really wants before anything else. Good luck, and if the situation indeed calls for you to get away from her, then I hope you see it soon enough to get clear without callateral damage.