I know that there were no other test subjects alive in Portal 2 (excluding the ones in the co-op), but were there other test subjects alive in Portal? You never see them or anything that would suggest their (living) presence in the facility. I would imagine that GLaDOS had other test subjects since GLaDOS had planned to kill you. But is there any proof of other test subjects?
I am not referring to the ones found in co-op in the 1950s cryogenic freezing. I am asking if there are any alive in the more recent Aperture Science testing course excluding the ones from co-op. (directly after GLaDOS had been activated)