Yes you can check for leaks in your plumbing without water. Do you have an air compressor? Air and water will leak through the same tiny holes. I would not recommend using more than 15 psig and let it set for 24 hours before rechecking. Exception, air testing is not recommended for use with plastic pipes! Compressed air means stored energy and is dangerous in plastic.
If you have a leak it will show up within 15 minutes; if you don't have a leak it will hold pressure for a week (with minor fluctuations for temperature change). Let 'er rip, Fartman you have the bull by the tail!