What is involved with a perk test?
A percolation test is used to determine the absorption rate of the soil. Basically you'll dig a hole (or bunch of holes), put water in it (them), and time how long it takes for the water to go away.

It's probably not something you could do on a property you don't own, as it involves digging holes in somebody else's land. You could ask the seller if you can run the test, maybe they'll let you.

If you do run the test yourself. You'll have to check with the local government, to determine what they consider passing.