Anyone have any experience testing In-App Purchases through the Amazon Store?

I'm currently working on a game project for a client and one of the requirements is Amazon Store support for In-App Purchases. I'm now trying to figure out how to test Amazon IAPs.

Documentation says I need the Amazon App Tester App but I can not seem to get this app installed… I downloaded their store onto my phone and when I search for the app I get a blank screen. It literally doesn't load any results…

Does anyone have any experience with this? Any insight on how to get testing done would be hugely appreciated! Thanks!