Bug 1132700 - Convert Mozmill testSafeBrowsingNotificationBar #91
Thank you for the feedback!
This test loads not about:error but about:blocked, with has similar issues. I've moved the time.sleep() lines.
I am not seeing any timeout issues today.
Regarding marionette.get_url(), that requires content context, and for the method you asked about, we are otherwise always in chrome context, including closing the tab after the url check.