Source : Free On-Line Dictionary of Computing

Intrusive Testing
     
         Testing that collects timing and processing
        information during program execution that may change the
        behaviour of the software from its behavior in a real
        environment.  Intrusive testing usually involves additional
        code embedded in the software being tested or additional
        processes running concurrently with software being tested on
        the same processor.
     
        (1996-12-01)