ATGMs fly at the same speed as RPG7. In fact most wire guided ATGMs are slower than RPG7 iirc. The test is just to demonstrate the APS' ability to tilt and deal with projectiles designed for top attack like Javelin.
I'm guessing they could easily test it against a HJ-10 and HJ-12. The RPGs just fly faster, making them arguably more difficult to intercept for an APS compared to any ATGM used by militaries around the world.