Abstract: A test tool for testing application programs of the type that are deployed on a server computer for access by multiple users over a network is embodied in a computer program comprising a command module and a core module. The command module contains a number of different commands, each of which performs a different user function of the application program under test. Each of the commands comprises a series of programmed instructions that cause a computer running the test tool to perform a user function of the application program under test via a client connection to the application. Each command has an execution segment and a verification segment. Each command is also assigned a unique name. A test operator can then create test scripts containing any desired sequence of command module commands using the simple names assigned to each command. The command module is rewritten and/or customized for each different application program to be tested.