Yes and no. There is a BIT for each unit, (now I don't know the exact details, but this is how I understand/remember it) but the pyrotechnic devices is tested b

Yes and no. There is a BIT for each unit, (now I don't know the exact details, but this is how I understand/remember it) but the pyrotechnic devices is tested by running a low level current through it to see if it has been fired/failed. The actual seal is verified via testing prior to aircraft certification, and checked in production using helium.