Testing takes on many forms and must adapt to every type of software, from traditional data processing applications through embedded real-time systems to client-server and distributed systems. Starting points for your testing efforts could be the following texts:
William E. Perry. Effective Methods for Software Testing, New York: John Wiley & Sons, 2000.
Matthew A. Telles. The Science of Debugging, Scotsdale, AZ: Coriolis Group, 2001.