Waldemar’s blog

Some of you may already know Selenium. Basically it’s free and open source tool for web application functional testing. It’s mainly know as replacement for HP’s QuickTestProfessional. I’ve recently discovered Selenium as very helpful for automating data setup for load testing.

Here is a small description howto setup Eclipse and run Selenium script through it.

1) Download Eclipse IDE from http://www.eclipse.org/downloads/
2) Download Selenium RC from http://seleniumhq.org/download/
3) Download Junit from http://www.junit.org/
4) Create new project in Eclipse:

• Go to File -> New -> Java Project
• enter project name e.g. “Sample”
• Click “Finish” button

5) Import Selenium and JUnit packages into the project:

• In Package Explorer right click project “Sample” and select Properties
• Go to “Java Build Path” then select “Libraries” tab
• Click “Add External JARs” and import junit-4.7.jar and selenium-java-client-driver.jar

Now our Eclipse environment should be ready. Next step is to prepare a test case in Selenium IDE. I’ve prepared small test that searches for “linux” word in google. To export test case as Java, in Selenium IDE go to Options -> Format -> Java (Junit) Selenium RC. As a result you should get something like this:

Default Junit code generated by Selenium doesn’t use Selenium RC. Because of that I updated the code a little bit to connect to localhost Selenium RC on port 4444. Here is updated version:

Now, lets add it in our Eclipse project:

• In Package Explorer right click on our “Sample” project and select New -> Class
• Enter class name “Untitled” and package name “com.example.tests”
• Click “Finish” button

Before we run our test, we need to start Selenium RC. For that open command line and under selenium-remote-control-1.0.1/selenium-server-1.0.1 run command “java -jar selenium-server.jar”. It will run Selenium RC server on default port 4444.

Now, to start the test just select Run -> Run As -> Junit test. It should open two IE browsers. One for Selenium RC and second with Google results for “linux” word.

Because we run Java code, it’s only up to us how we want to run the test. Below is our example update to search for “linux” word in a loop 5 times with 5 seconds intervals.

Correct me if I’m from but I always thought that for particular transaction there should be only ONE average response time. But it looks like it’s not the case in LR Analysis.

I recently discovered that by changing granularity on average transaction response time graph, Analysis also recalculates average times under the graph. In my understanding granularity is responsible only for making the graph easier to read and thats all it should do. But by changing granularity we are also changing how many points LR actually counts which results in different average response times for different granularity.

So shame that this is not mentioned in the manual. Of course according to HP support it is mentioned there and this is a feature, not a bug

So my tip for today: be careful when looking at response times on average transaction response graph. Use “Summary” page if you want to omit any mistakes.

Web (HTTP/HTML) scripts in LoadRunner are implemented using C programming language. And like always with C, you should remember about some basics. One of them is that few string handling function can return NULL value instead of correct pointer which will definitely lead to exception like the one below:

Basically if you see message like this, it is not any internal LoadRunner error. It means that you made a mistake in your script and you need to fix it. But let’s start from the beginning with some example:

This small piece of code takes parameter MESSAGE with value “hello_world”, then search for the first space character and display the string starting from that place up to the end. Function strchr() is responsible for searches for the space character. If it’s found then strchr() will return a valid pointer (something like 0xb36ac56e). But if the space is not there (which is our case since there is no space in the hello message), strchr() will return NULL which refers to 0×0 memory address location.

Such memory address is a very special address. Basically any read attempt from there is threated as incorrect operation and results in memory access violation (not only in LoadRunner).

Now, howto deal with it? If you see ACCESS_VIOLATION, in most cases it means that your LR script is working on incorrect/incomplete values. You are responsible for error handling in your scripts and you should always:

• validate parameter’s values
• check results of C functions to handle any errors, unexpected conditions
• remember that you can’t always expect correct values and you need to handle it as well

Here is our example with fix showing howto deal with ACCESS_VIOLATION. We are calling strchr() function and checking if value returned is not NULL.

More details about NULL pointer here http://en.wikipedia.org/wiki/Pointer_(computing)#The_null_pointer

The easiest way to measure web app performance is just to record a script and run it in HP Controller. Such test is fast and simple, but it’s also incomplete and incorrect. It’s because LoadRunner is not the tool for performance measurements. It’s a tool only for generating the load on the server (Load Runner – tool for “Running” the “Load”).

So how to deal with that?

LoadRunner finishes taking measurements when web page code and all non-HTML elements (jpg,gif,js) are download into the clients memory. But starting from that point the browser need to form UI and display it to the user. And that’s the part that LR is actually skipping. Full end-to-end test should measure time between clicking “submit” button (or whatever triggers a call) and displaying full page within the browser. So how to do it in LR? The quickest answer is “not possible”. For that you need to use QuickTest Professional.

In that case of course you need at least two scripts. One prepared in LoadRunner and second prepared in QTP. Each script will have different task to accomplish. LR script will generate the load on the server simulating different amount of remote users connecting with AUT. QTP script will measure times only for one user, and that’s what we actually need. I believe every single web user care only about how fast page works in his browser. Not how fast it works across all remote users together in average. Of course one is connected with the another.

LoadRunner and QTP have one thing in common – transactions. And basically to measure end-to-end time in QTP all you need to do is to use transactions and remember to synchronize each page correctly. By synchronize I mean to finish transaction when page is fully downloaded and displayed to the user. One solutions for checking when downloading is finished is to call WaitProperty on browser’s status bar element. Example QTP code:

If you have LR and QTP scripts already in place, now just add them in HP Controller into your scenario. To see QTP scripts in Browse window just change File Type from “Vuser Scripts” into “QuickTest scripts”. One think to remember is that you are allowed to run only single QTP instance at a time so hacks like few QTP scripts running simultaneously are not possible (unless you are using Citrix which is another story).

Only with such scenario you are able to measure full end-to-end performance.

If you ever wondered howto solve Capture The Flag contest exercise, here http://hackerschool.org/DefconCTF/17/B300.html is a good detailed description. Have fun…

http://r00tsecurity.org/files/zf05.txt Joanna called “Biggest mailing list troll” heh

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Some time ago I described how to test web services in LoadRunner with HTTP/HTML script. Right now I would like to describe the correct way – testing with Web Services script.

First of all we need a web services. And there is one available exactly for training. Here is the WSDL http://soatest.parasoft.com/store-01.wsdl. I hope that folks from Parasoft don’t mind we are not using SOATest

In any case, we have an WSDL file. Now lets create new script.

Click File / New and select “Web Services” from list of available scripts types.

Now, when we have new script we should see new toolbar under the standard one. It allows to add Web Services description to the script (from WSDL file), add XML request using form and add XML request from file. So lets click on “Manage Services” button and then “Import”. Enter WSDL url http://soatest.parasoft.com/store-01.wsdl and click “Import”.

After WSDL file is imported, just click “Apply” and “OK”. From this point LoadRunner has description of our web services so we can use it send some requests. We will actually create two requests. One using “Add Service Call” and second using “Import SOAP” buttons from toolbar.

Click on “Add Service Call”. In “Operation” dropdown list select value “getItemById”. On left side select “id” under Input Arguments tree node. Then on right side type “1″ into Value editbox.

Now our script should look like this:

Now lets add Web Service request using Import SOAP. Lets assume we have XML request saved in file on the disk. Here is an example:

Click “Import SOAP” button and select your file. Change type from “Web Service Call (Recommended)” to “SOAP Request”. Select URL from the list, and type into SOAPAction this value “getItemByTitle”. Click OK.
Now we’ve added second call that ask for book details for title “Linux”. Our script should look like this:

As you can see, each request contain “ResponseParam=response”. LoadRunner will automatically save response XML into parameter with name “response”. We can easily display this parameter by addind

after each call. So at the end out script should look like this:

At the end lets run our script. Output should be something like this:

The easiest way for checking web service response in HP LoadRunner is by using XPath query language. LR API contains few functions designed especially for dealing with XML.

Now, lets say we have sample web service for on-line book store and we want to ask what is the author for book id 123. Our web service can send following XML as a response:

For checking if the “author” element within XML response contains “John Smith” value we will use lr_xml_get_values() function. Here is the code that calls web service and checks if the value is as expected:

First argument in lr_xml_get_values() call is parameter name that holds response XML. Second argument in name of new parameter that will hold author value extracted from response XML. Third argument is XPath query that extracts author element value.