I'm new to 1D Mark III. How to check for AF problem?

Dear all

I am now a proud owner of 1D Mark III. Coming from 1DMkIIn background, this camera really feels good in terms of button layouts and screen options. Body serial no is 548188.

So, far my AF for one shot is fine, but I really have not tested it for action using AI servo. I have another 4 days before I can return the body back to the seller.

How can I ensure, this body is not one of the AF affected?

Can you please suggest me few AF testing methods, so I could be on the safe side and enjoy taking pictures, rather than being worried about the AF !

Thank you in advance.

--
Ajimon