Test either the squat or the deadlift. Since some people are built to pull or squat, this leaves the athlete some room to work with. I also have no problem with an athlete choosing the trap bar deadlift. Now I know every powerlifting purist will scream, "Heresy!" in regards to the trap bar, but I think it's safe to say that powerlifters don't need to be making athlete decisions.
The test can be comprised of a one-rep max (1RM) derived by using a rep-max calculator for up to 10 reps. (No, the rep/max calculator doesn't give your projected max with any high level of accuracy; it's just a tool to help gauge performance.) Using just a 1RM as the sole way to test an athlete's strength is pointless.
And let's be honest, does anyone really care if an athlete does a 500-pound single or 425 for five reps? Strong is strong and the only people that fail to see this have yet to take a snap or get their picture in the media guide. To convert your rep max to a projected 1RM, use this simple formula:
Weight Lifted x Reps x .0333 + Weight Lifted = Projected Max.
- 2.5 times bodyweight: Awesome
- 2.0 times bodyweight: Good
- Less than 2.0 times bodyweight: Work harder
Note: These tests are just part of the equation. You need balance across several tests. More info here.