pauster, you need to have a trustworthy valve included for the water test. You need to know that the 'rig' you're using to test will hold pressure in and by itself. Make sure to have 4 wraps of teflon tape on all treaded connections and o-rings where applicable, if you glue any parts of it together make sure you follow the directions for cure time before putting any pressure through it.(personal experience - I almost had my head taken off by a 3" cap that I had just glued and one of my coworkers shoved 30 - 40 psi into the line) I would make the tester so that it ended in a 1.5" M/A that you could screw into one of the returns and cap the sawed off end to do the test. Definately have a pressure gauge on the tester. Take the pressure up to 10 psi and shut the valve. Watch the gauge, a big leak won't even let you hold 10 psi without the water still running through it, a small leak will 'tick' down (~1/2 psi at a time drop). If you see no movement on the gauge after a minute, you're good, though if the line is good it will hold that pressure indefinately.
Welcome to the forum! If you have any ?s about what I've suggested, post them and I'll get back to you tomorow or Sat.