Starting Browser with Notification

I have a test case that changes a password. The script itself works fine, but i want to add a verification step.
When the Password is changed manually (with the same steps as in test case), there is a notification shown ("password changed successfully) that has an OK button that has to be clicked. When i launch the test case, the Browser doesn’t display this Notification. For verification purposes, I want to add two steps:
WebUI.verifyTextPresent(‘Password changed successfully’, false)

How can i launch the Browser with Notifications enabled for one testcase?