When an interview is not a discussion, but rather a test, it is a bad interview.
Another interviewer told me at the end of the interview to submit an application and they can get an offer emailed to me by the end of the day. We did a collaborative white board design session and spent a lot of time just talking.
Either all of the job offers I've gotten have been mostly just discussions or I talk tech so much I can't tell the difference between an interview and a typical day at the office.