A rolling test stand is a really nice tool to have. I have had one made by KFC-Zeller in Germany for years but I was not using mine because it was not installed permanently.
I modified it to permanently install it on my workbench ready to use
The STL files for the blocks are available on my GitHub if you want to make one for yourself. All that you need is some 3mm and 6mm linear rods. The trolleys can be found on AliExpress. (search for: Track Roller Test Stand)