I agree with the others that therapists who basically try to head f**k you with stupid "tests" like intentionally misgendering you to see what your reaction is, is a crap therapist.
While I do believe that they have to have some sort of procedure to verify the diagnosis before recommending treatment, I don't deal well with a therapist that plays games like that and I've personally stood up in a session and ripped certain therapists a new one for that sort of behavior. This is one of the reasons why I don't even go to therapists anymore. I've been to so many of them that I know their job inside and out, when they have no clue, and even what their supposed recommendations for me are going to be before they say them.
Yet I know other people who swear by therapy and say they had a wonderful experience and the therapist really helped them. Seems like a crap shoot to me. Unless one comes on a very high recommendation from someone you trust.