Using Selenium to test input validation

When testing for security, it is important to test that the application under test (AUT) handles unexpected input properly, i.e. does not enter an unsecure state. A typical example of an unsecure response to an unexpected input is to display an exception that reveals information about the system configuration that can help a malicious user breaking in to a system.

As I blogged about earlier, I am trying to use Selenium to do security testing. In order to be able to test how the AUT handles being passed a value that is not present in an HTML dropdown list, I created a Selenium extension that adds a new option to a dropdown list and selects it. This way, the test may add a new value before submitting the form to the application.

Here is the code for the Selenium action.