Testing For Fps Drops

Hey everyone,
I was wondering is there a way to test performance for low end devices/test my code to see if it will be consistent over fps drops?

I thought i implemented a good way to keep gameplay smooth while some fps drop happend. However it seems it might not have gone as planned. Is there a way i could test different fps level to test that code.
eg test fps at 55fps, 50fps, 45. to 30 fps

Any ideas?

use setInterval() instead of engine.runRenderLoop()

This way you can render when you want for testing