Just tell them you know how to drive a forklift and to not waste anyone's time with a test. It worked for me. I was signed off for the forklift (and reach truck and order picker and blue lift) on my third day, without ever having done more than watch the training videos.
On the one hand, I used to drive a forklift daily and had a license for it. And though that was a few decades ago, I've driven them plenty of times at Lowe's in the past year+ without a hiccup - it was like riding a bike. The other equipment is equally as intuitive and simple to operate.
On the other hand, I was kind of taken aback by the safety standards of simply taking my word for it that I could operate the equipment and handing me licenses.
As for your test, the best advice I can give is to just take your time. It's a skills test, not a race. Best of luck!