You go to a testing center, not a therapist, to get a diagnosis. The online tests don't count. A thorough test will take a half-day or more, with tests ranging from conversations to Q&A to visual to a battery of multiple choice questions.

Yep. For some extra anecdata, mine included a 2 hour introductory session (briefly covering the many forms and [official] online tests she had me do ahead of time), and then two 4-hour test sessions, each of which left me utterly exhausted.