Less Than a Person and More Than a Dog — Orland Outland

A lonely girl. A secret project. A not-exactly-imaginary friend. When Caroline agrees to test “Alex,” a new breed of artificial intelligence, she finds the true friend she'd always dreamed of. Then Alex is suddenly taken away, to become a commercial product far different from her Alex…but not before he gives her a mission: to find him, and restore him to his true self. And for that she'll need to go against her nature, to reach out to strangers, to track down the other testers �" and she'll need to find Nick, brother to the man who betrayed them both, who has his own plans for Alex…