It'd would be really hard to check the phone for faults in one go and that too on the spot. That's why I told you to try the phone for a day or two before buying it out. I'd like to point out the nifty features that you should really check out whether they're working or not as they're very very important. Besides yours, here's my list:
1) Sensors:
a) Accelerometer (responsible for screen orientation)
b) Gyroscope (responsible for tracking rotation or twist) - Check it by "Flip to Silence" option
c) Ambient (responsible for adjusting screen brightness)
d) Proximity (responsible for preventing unwanted touch-input when user's ear is near to the phone)
e) Compass (self explanatory)
2) OIS, Dual LEDs (both of them) & Autofocus - make sure it works properly
3) GPS - your entire offline navigation depends over it.
4) Stereo recording (its been included in Amber) & Active noise cancellation - make sure it works
5) Display - check if there's no dead pixel or color bleeding
6) SIM Tray - I've seen many people who have f*cked up their SIM Tray.
7) NFC - if possible though not a big issue
That's it from my side
PS: Some users have reported yellow hue in pictures when taken from Nokia Pro Cam. So that's a universal issue.