I think talking to him directly about this is pretty important, especially the part about how he seems to you to be "testing you" and you wonder if this is true? Tell him you feel he tries to irritate you to get a response, and this seems to occur when things are going well, and you wonder if this is some kind of technique he is using? If he agrees this is it, you could also state you prefer direct communication rather than testing. But you may find out your perceptions are not correct, as tree said was the case for her. Or they may be. In any case, even if you don't end up staying with this T, having a clear and direct conversation about this issue will only help you in the future with another therapist or with other people in your life with whom you need to communicate directly. Good luck.

(Does he ask you to call him "Doctor"?)

FWIW, my T uses himself in therapy and also uses our strong and close relationship to help motivate change. I think this is not uncommon. At least with my T, there has been nothing sinister about it.