sverx at the SMS Power Forums is developing a tool suite for the Sega Master System that is inspired by Artemio’s 240p Test Suite. So far it includes some basic but very useful video tools and a graphical controller test. Sverx will post the source on Github when it reaches v1.0, and is open to user requests and feedback. It works on real hardware, and on Game Gear and Genesis as well.
The latest version (May 2019) of the suite has just added the ability to identify the MegaDrive’s VDP by testing the sprite zoom capabilities. Follow its progress and download the free ROM here.