A simple test piece that I have created to test the Prusa Multi Material Unit.The test consists of five pieces, each one is numbered. Simply import the parts into Slic3r, and have each numbered piece correspond to each extruder.
Alternatively, I have included a GCODE with everything set up already, which I used on my Prusa MK3S and MMU2S unit.
Simply load up five colours of your choice, and print.
This test is a quick and easy way to make sure that your MMU2 or MMU2s is working properly, and it looks cool too!