The use of new test tools can significantly improve the efficiency of Web site load testing and scalability testing. A load test tool can emulate hundreds or even thousands of users accessing a Web site during short periods of time. Because these tools are relatively new, they can vary considerably in price, reliability, and capabilities. You'll want to consider the product's limitations and capabilities regarding OS platforms, compatible browsers, secure HTTP capabilities, and the quality of the scripting language. Cost is often based on the number of simulated users.
Some tools have a demo version available.
Regression Test Tools. These are most useful for the automation of tests that will be repeated at least several times. The effort that may go into scripting and debugging these tests is only justified if the same test scripts can be reused without major modifications. For example, a set of tests might need to be carried out each time a new build of your site's CGI software is modified or each time there are modifications to your Web site database stored procedures. Such tools can also be used in tandem with load test tools for stress testing by repeating a suite of tests under varying load conditions.