This custom module for the Grinder load testing framework allows execution of Visual Studio "webtest" files. It supports parameterization, capturing of variables in HTTP responses, and response validation using regular expressions. Test scripts may be logically grouped into test sets, allowing them to share variables and captured values. Test sets can be run sequentially, randomly, in a specific thread, or according to a percentage-based weighting. A correlating test runner is also provided, making it easier for you to find and capture values in your HTTP responses.
We have successfully used this module to run load tests of more than 300 virtual users, with a scenario involving 21 different webtest scripts recorded in Fiddler.