Abstract: Extensible automated testing software provides reliability, user extendibility, scalability, and multiple simultaneous testing support through the use:of modules which the user may employ to set up and run test scripts. One or more job files are passed to an execution harness, which then starts a System Runner Process on a host specified in the one or more job files if one has not already been started. A connection is then made between the execution harness and the system runner process and one or more Test Runner Processes are spawned. These Test Runner Processes may be spread out over various hosts. Each of these Test Runner processes calls procedures to execute one test script at a time. Since multiple instances of the software may be run simultaneously, this allows the software to properly manage multiple tests running on multiple hosts being executed by multiple users.