Caleb,, the pressure test is for testing the integrity of a sealed system like the water jackets at LOW PRESSURE.
Testing the cylinders is a different story as the rings are designed with a gap so they won't seal. If they do seal the top of the piston will be compromised or pulled in half. there is a test commonly called a "leak-down" test of the cylinders. This is done by injecting air into the cylinder and "listening" to the crankcase for air leakage and a guess as to the severity of the leak.
Dave Neptune
