ideally you should try to avoid testing/debugging code as the root user on your system, as bad things could happen to the system leaving you up the proverbial creek without a paddle. chroot/fakeroot allow you to create a "fake" file system that looks like the real thing to the application. scratchbox goes one step further and lets you fake entire platforms, which allows you to test code for embedded systems (mobile phones, settop boxes etc) without having the hardware. the tools can even support gui apps using utils such as Xephyr. google any of these for more info. can you gives us more info about the sort of app you are trying to test/debug?
