This test fails intermittently for me with an assertion error: ```AssertionError: u'00:00' == '00:00'```, so it seems like it's not waiting long enough for the elapsed time to change. I suggest adding something like:

```self.wait_for_condition(lambda m: not self.marionette.find_element(*self._elapsed_text_locator).text == "00:00")```

before the assert. This allows the test to pass consistently on my machine. However, I am seeing another issue: after running the tests a few times in a row I start getting errors from ```kill_all```, which is unable to kill the video app. Stack trace is here: http://pastebin.mozilla.org/2076268

Particularly strange is the fact that I cannot even kill the video app manually on my phone after this starts happening - only a reboot will get rid of it.  This sounds like a bug to me, but I wanted to document it here in case it starts affecting our tests. Note that I see this behaviour with both the current version of the test and with the version that includes the wait that I suggest above.