This was part of how my ADHD was diagnosed. I did a full day of testing at a specialist center. First I had a conversation with a nurse, then a psychologist, then they had me do a similar test (but in a controlled environment and I also had face tracking and a motion sensor monitoring my movement). After the test, I was given lunch and a dose of adhd medication and about an hour break, then they had me do the test again. After that I met with a psychiatrist who walked me through the test results. Then I had another break while the three specialists met to discuss my case and make a diagnosis. Finally I met with the three to hear the outcome (I was also given a full write-up of my results from the day).

My one surprise from this article is that "play a web game for 18 minutes" in an uncontrolled environment was considered enough testing for a diagnosis!