This is a kind of resolution test, but not really. Resolution is a more complex thing.
But this test shows wether printer can actually somehow react to smallest details and show in any way or they will get lost.

One side of the thing has indent from 0.025mm to 0.1mm in 0.025 steps (4 total)
Other side has extrudes from 0.025mm to 0.1mm in 0.025 steps (4 total) and 4 narrrow (0.5mm) bars also from sticking out from 0.025mm to 0.1mm (4 total).

Print it and check what sides you can actually see.

I get 0.1mm and 0.075 but 0.05 and 0.025 get 100% lost.
I have y-bed style printer with 16 microsteps with 16t pulley (so, 100 microsteps per 1mm).

Rotate the thing so the testing indents will be perpendicular to tested axis. And the triangles should be on the bottom.