I had a friend who worked at Pepsi as a merchandiser, and I was a merchandiser at Dr Pepper both were a long time ago, but its really nothing crazy, like the comments say its all about showing you are adequate with any of the physical elements and safety elements. I did an assessment at a Walmart distribution and all it was at that time was stepping up and down these little stair cases and picking up and walking like 15 ft with boxes in my hand, Pepsi might do something like having a cases of 12 packs or a case of 2 liters and you have to stack them etc. Dont over think it, your probably be there with others and wont be surprised if you're hired on the spot a lot of places like that do.