This testfile benchmarks your stepper performance. You give the Stepper a lot of motion and you can check different things:

1. How warm is my driver!?
2. How warm is my stepper?
3. Can the stepper handle the motion?
4. Is the Motorcurrent setting correct?
5. Are the layer shifting?
6. Is the jerk-parameter correct?
7. Is the acceleration correct?

Print it with fast print-speed to give your steppers a lot of work.
If your printer passes the test with high speed, look at the print result and change the different parameters. If everything looks fine, the power of your printer is perfect. Maybe you can retry the test with higher speeds and accelerations.