How to test things easily without affecting installed ports?

Hi, I need to test some things, mostly whether a port I maintain build correctly or not. In addition, I do not want to affect software I actually use for my everyday work. I was thinking about additional MacPorts installation, which could have it's own directory tree to deal with, but it seems difficult to me. Multiple Mac OS X installation does not sound good either, does it? What would you suggest? Cheers, -- Mike.