I'd suggest having a whitelist of allowed process names that are allowed to be running during the test as that user. If any other programs are running when the program starts, it should not allow the test to be started until those programs are shut down (add a "kill all" button for newbie users). It should also have a watchdog that polls to make sure that the system is still clean. If it finds any unwanted programs, it should give the user 10 seconds to kill them or fail the test (or require a password to ignore this process). If you can do this in the same thread as the testing program, and in such a way that you can't just attach gdb and pause execution while you google the answers, you're onto a winner.