I agree she's testing you. Part of me suspects that she's hoping to see if you're moving on to appease her guilt. I think she's under the impression that she can just be "off the hook" which would infuriate me...
The night BF told our therapist he wanted out of the relationship we came home and he was the nicest he'd been to me in a long time. It was creepy. I said, "What are you doing? I don't understand."
I wasn't DBing then. I was just kind of being real with him. Like I'm not going to pretend he didn't just break up with me and act all nice - I was normal, but I was like Um, not sure what that's about.
I'd just be real- authentic. Maybe not respond. Is she giving you anything through this exchange? If not, you don't have to accept it or take care of her.
