I was set-up with an interview via a staffing agency. The interview consisted of 1 hour of a skills-based test and 1 hour of speaking with the hiring manager. It was fairly straightforward. The time was well-managed. The skills-based portion wasn't rigorously managed. I set a timer to make sure I adhered to the time limit. However, as I got closer and closer to the end of time I thought for sure they'd come and stop me. This never happened. To keep it honest, I stopped working at the end of the first hour and went to find the interviewer. I don't know if this was a "test" too but I would encourage you to manage your time. They won't do it for you and you may appear untrustworthy if you allow it to significantly run over.