Performance testing ASP.Net applications with Microsoft Application Center Test

• Download source files - 215 Kb
• Download demo project - 7 Kb

Introduction

This article explains the working of an application/utility  that enables Microsoft ACT test ASP.Net applications.

Background (optional)

Microsoft Application Center Test (ACT) is quite simple and a nice tool to test the web applications' performance. It lets the user record a session and then through vbscript generation it enables the user test the application simulating the real world environment (controlling number of users, concurrent sessions etc). But for ASP.Net applications, there is a problem with ACT ver 1.0 that it does not support ASP.Net applications because primarily ACT was developed for ASP/generic html applications and it lacks the functionality to handle the ASP.Net viewstate. Nevertheless, there is a workaround that makes it possible using ACT for ASP.Net application testing but it requires manual editing of the vbscript code. This article describes a utility that automates the task of manual editing and make it simple for the developers/testers to modify the ACT vbscript code. Users just need to copy the ACT generated code into the ACT.Net conversion utility application and it gives back the code that can be used in Microsoft ACT to test the ASP.Net application.

Using the code

Well, basically you won't need to do much with the code, you can simply download the demo application and use it to convert the vbscript code to make it support ASP.Net application testing.

Following are the steps to follow in order to use the demo app.

Instructions:

1. Record a test in Microsoft ACT.

2. Copy the vbscript from the ACT recorded Test.

3. Paste the text in the "Source"text field in ACT.Net Conversion utility

4. Press Convert

5. Once it shows complete, click on "Output"

6. Copy the script and then paste it back to the ACT test. (Alternatively you can create a new blank test and paste it).

7. There is a limitation in Microsoft ACT, it doesn't allow you paste very large scripts. To overcome this problem, access the {testname}.vbs file (in your ACT project folder) through your browser and open in notepad/wordpad. Paste the new script and then save it. Reload the project in Microsoft ACT.

8. Run the test!.

9. There is a possibility that you may get some errors with the function Mid(..,..). It happens when the viewstate size is very large. To resolve this issue, repeat steps 3-7 with an increased buffer size (300000 or more).

For those who are interested in the code (or may like to make some of thier own changes to the generated code) here I explain how the application works

The code is pretty simple to understand. What it does that it updates the vbscript code generated by Microsoft ACT by inserting variable declarations, setting the request/response buffer size to hold the entire viewstate, storing the viewstate data in a variable and in the next request appending that data, stored in the variable, to the request object.

			// declare the text to be isnerted

			// we need to locate the following line of codes and then replace them with the new code that supports ASP.Net viewstate

			System.String searchCode = "strStatusCode = oResponse.ResultCode";
			
			// nees to set the buffer size large enough to hold the viewstate (in response object)

			System.String searchCode2 = "Set oResponse = oConnection.Send(oRequest)";
			System.String manualCode2 = "oRequest.ResponseBufferSize = "+this.txtBuffer.Text   +Environment.NewLine+"        Set oResponse = oConnection.Send(oRequest)";
			
			// need to declare two variables

			System.String searchCode3 = "fEnableDelays = False";						
			System.String manualCode3 = "fEnableDelays = False "+Environment.NewLine+"Dim strViewState "+Environment.NewLine+"Dim Pos1, Pos2	";
			
			// this piece of code will be injected to the vbscript to search the viewstate data in the response text and then extract and store it in strViewstate variable. 

			// this strviewstate will be used in the next request to send the data back to the server

			manualCode.Append("	strStatusCode = oResponse.ResultCode "+Environment.NewLine+"	' Manual Code injection- begin"+Environment.NewLine);
			manualCode.Append("	If InStr(oResponse.Body, \"__VIEWSTATE\") Then"+Environment.NewLine);
			manualCode.Append("		Pos1 = InStr(InStr(oResponse.Body, \"__VIEWSTATE\"), oResponse.Body, \"value=\")"+Environment.NewLine);
			manualCode.Append("		Pos2 = InStr(Pos1, oResponse.Body, \">\")"+Environment.NewLine);
			manualCode.Append("		strViewState = Mid(oResponse.Body, Pos1 + 7, Pos2 - Pos1 - 10)"+Environment.NewLine);			
			//manualCode.Append("		Test.Trace \"StrViewState After extract:= \" + strViewState "+Environment.NewLine);

			manualCode.Append("		' Manually encode viewstates:"+Environment.NewLine);
			manualCode.Append("		' Replace all occurrences of \"+\" with \"%2B\""+Environment.NewLine);
			manualCode.Append("		strViewState = Replace(strViewState, \"+\", \"%2B\")"+Environment.NewLine);
			manualCode.Append("		' Replace all occurrences of \"=\" with \"%3D\""+Environment.NewLine);
			manualCode.Append("		strViewState = Replace(strViewState, \"=\", \"%3D\")"+Environment.NewLine);
			manualCode.Append("	End If"+Environment.NewLine);
			manualCode.Append("	' Manual Code injection- end\""+Environment.NewLine);
			modifiedCode.Append(this.txtSource.Text);	

			
			modifiedCode.Replace(searchCode3, manualCode3);
			modifiedCode.Replace(searchCode2, manualCode2);
			modifiedCode.Replace(searchCode, manualCode.ToString());

History

Initial: 06/06/06. Hassan Syed Last updated on : 07/06/06. Hassan Syed