I have been testing our .Net web app for several weeks now and the only continual error that I receive during a test run is to do with ViewState.
I had some initial problems setting up the test, as the site I am testing consists of a series of stepped pages (a card application) and if data is not passed correctly after each step, then the app will redirect you to the previous page. These were resolved so I know the test run works as I can see finished card applications being written to the database.
The problem arises when the test has been running for a while. We are currently at 150 virtual clients and we receive the following exception about 100 times an hour:
- Code: Select all
System.Web.HttpUnhandledException: Exception of type System.Web.HttpUnhandledException was thrown. ---> System.InvalidCastException: Specified cast is not valid.
--- End of inner exception stack trace ---
at System.Web.UI.Page.HandleError(Exception e)
at System.Web.UI.Page.ProcessRequest(HttpContext context)
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
I set enableViewStateMac to false in the web.config as this exception was originally manifesting itself as a corrupt viewstate that was deemed invalid.
The error is generated by any of the stepped pages, it is not just tied into a single page, which confuses me slightly.
I was wondering if the error is due to a slow down in the site? When ANTS load is running through a test script, does it wait and wait on a request until timeout, and then continue to the next request in the script if the previous one fails? I so then I guess this would break the application process as the next step would always redirect to the previous, or the beginning depending on what had happened.
I am just trying to get my head round why we are seeing so many of these errors so any pointers would be greatly appreciated.