Testing a M8/M9 when buying second hand

[pieter]

Hi,
My name is Pieter from The Netherlands. Please allow me to extract some knowledge from the well of wisdom that is the rangefinderforum.

Since a while I have been shooting with a Sony Nex-5n with some M lenses. What surprised me was how I loved shooting manually. It just seems to make the process of taking a picture a much more satisfying and creative one.

So for the last couple of months I have been thinking about buying a second-hand M8 or M9 (I have to admit I'm still on the fence between these two fine cameras). For the kind of money involved in such a purchase I prefer to deal with somebody face to face instead of having the camera sent to me by mail.
So when I find a camera for a fair price I will probably go by to pick it up myself. Buying second hand I expect no guaranty beyond the doorstep, so I would like to make sure the camera is in good working condition when stepping out the door with the camera (and leaving my hard earned cash behind)

What I would like to ask you, the good people of this fine forum, is if you could help me point me towards some things I should look out for when buying an M8 or M9? Is there a way to test a M8 or M9 quickly during the process of buying one second hand?

First of all I already have an M-mount lens (biogon 35mm f/2). Second I feel that for this kind of purchase I should be allowed to test the camera for about an hour. Thirdly I have a macbook laptop with lightroom 4 installed.

How would you test a M8 or M9 in one hour using the biogon 35mm and a laptop with lightroom?
Take different pictures at different iso ratings?
Maybe pictures with the lens cap on as well?
Make pictures of a white wall to see irregularities?

Bonus points if you could devise a complete test with time table within one hour. :P Any help would be very much appreciated, so thank you all in advance.