It all depends on who your inspector is... I've had the full gamut, from those that just plug into the OBD for the emissions test and slap a sticker on, to those that check the lights/glass/quick glance at tire tread if the vehicle looks good, to some that will throw it up on a lift to check the suspension, to one that actually did the proper full blown inspection - checking the brakes, steering, etc (to be fair, I was having an alignment done during the same visit, so they already had it up for work and the inspection was due, so I just had it done while I was there. They may have done less otherwise).
The rule of thumb, is if you tell them that you do all of your own work (or else they are your regular mechanic) and it is obvious that you keep things in decent shape, they'll just do the minimum they feel comfortable with. For the $21 an inspection costs (less if you're exempt from emissions), it just isn't worth it to spend a half hour or more combing through the full checklist (more if they take it out for a drive to check brake equalization like they're supposed to) unless they are going to get you into the shop for a repair too.
The full checklist can be found here:
http://www.nydmv.state.ny.us/broch/c-50.htm