ditto. (file IFR and put it in the remarks section)
Just tell clearance that you're conducting an "operational check flight", what direction, altitude, the distance you want , how long you'll be up, what you need from them and about how long you'll be out.
Also, here's some worthless, yet unverified trivia: unless you're a certified (or authorized) test pilot. You can't legally conduct a "test" flight. A former military pilot friend got jammed up on a ramp check with this one. Was asked what he had been doing, when he responded "conducting a test flight", he was asked to produce his test pilot credentials. After the FAA guy finished puffing out his chest, he informed my friend that ONLY TEST PILOTS can perform TEST FLIGHTS; all others (within the scope of this discussion) are "Operational Check Flights".
I wanted to throw the B.S flag at the whole situation but I had nothing to support it. Sounded about half true and about half crap to me....but I've not said "Test flight" since.........