There's only one test
https://trust.modelaircraft.org/
Thats good for a lifetime, is no-fail and free

You also need FAA registration
.https://faadronezone-access.faa.gov/#/register
It may ask you to register your drone, you only need a one time pilot registration good for 3 years that costs 5 dollars. If you hit the spot where you're asked to register your indvidual drone, just tell it you have a home built serial number 001, that screen is an error they know about.

Depending on where you're flying such as a club, you can get your AMA insurance at www.modelaircraft.org