Selenium is a free Web Application Testing System. It gained lots of popularity since it is available. It’s integration to FireFox – which allows instant record/replay as well as the scripting option - makes it a great tool for functional web testing.
BrowserMob on the other side leverages Selenium by providing an automated load-testing environment for Selenium scripts all configurable online via a Web Dashboard.
Tagging Web Requests
In my recent blog post – Get more out of functional web testing: How to correlate test reports with server side log information? – I discussed the problem that testing results are usually not linked to the log and diagnostics information captured by the application under test. The blog entry offered a way to link the two sides using HTTP Tagging via an HTTP Proxy. Tagging individual Web Requests allows linking each individual request executed by the testing tool with the transactions that are executed on the server side. Your logging framework or diagnostics solution can then take this tag and link the transaction to the originating web request.
Tagging Web Requests with Selenium
Selenium offers a feature to add additional HTTP Tags to each Web Request via DefaultSelenium.addCustomRequestHeader. This feature allows achieving the exact same result as I explained in my previous blog entry.
In order to make it easy for Selenium script developers to use this feature we (Patrick Lightbody from BrowserMob and I) came up with the following 2 requirements:
- every test case should automatically be tagged with the test case name. This ensures that we can link each transaction to the test case
- the scripter must have the option to change the tagged value within a test case to allow more granular linking to individual actions in a test case
The implementation for these requirements resulted in
- a custom TestRunner class (DynaTraceSeleniumRunner) that sets the default value for the HTTP Header to the current test case name
- a custom Selenium class (DynaTraceSelenium) that offers the scripter to change the value for the HTTP Header
With these changes a tester can now create a script like this:
When executing the script – the first request to the frontend URL will be tagged with the name “MyTestUseCase”. This tagged value will later be changed with the call to selenium.setTimerName meaning that all login web requests will be tagged with the value “Login”, all search related requests with the name “Search” and logout with “Logout”.
Using dynaTrace on the application that we are testing allows us to pick-up those HTTP Headers and enables us to exactly identify the individual transactions that came in from the individual steps in the test case.
Step 1: Starting from the Tagged Web Requests View
Step2: We can drill into the individual web requests that were executed, e.g.: lets see the 14 requests for the Search action
Step 3: Check the outliers
Interesting here to see is that the average sum for all Search actions was 764.32 ms. In the detailed drill down we however see that we had one request taking 10.45 seconds. With another Drill-Into we can examine the one request that took so long:
Step 4: Analyse Log Messages
Additionally to drilling into a transaction we can go the other way round by drilling from a problem to the originating test case. Let’s start by looking at the log outputs that were automatically captured bydynaTrace.