Some building inspectors will require you to pressurize the tubing before pouring , but this only tests for leaks and in over two thousand systems we have never seen a leak. Although, the potential for damage from sharp ends of rebar or reinforcing wire does exist, a more likely problem is kinking which will restrict the water flow later and will not show on a pressure test. 
If you need to pressurize, start by splicing all of the loops into one loop, then put a pressure gauge on one end, and a ball valve on the other end.     

DO NOT LEAVE PRESSURE ON DURING HOT WEATHER

DO NOT USE UNAPPROVED FITTINGS!!

HOSE CLAMPS WILL NOT WORK ON PEX!!   

It works best with at least two people, one person rolls the tubing, the other ties.