How do I perform a water test on the gutter guard?

First, make sure to get the mesh very wet, then spray the water on the roof to see how the water comes through the mesh and into the gutter. Secondly, put some wet leaves or pine needles on the mesh, lots and lots of them and even some roof sand grit or some debris straight off the ground, then put a lot of water on the roof to see how it takes in the water through the mesh and into the gutter.