Selenium

 I recently needed to create a test case for selenium that required a user to have just logged in to a Drupal website.  Often when running selenium tests, the browser may already have an authenticated session, so the test will need to detect this and then logout.  Of course with Drupal you can always just go to the url ?q=logout to make sure you are logged out, but this way is more fun and makes a good example for using logic in Selenium tests!