[There is a timeout](https://github.com/edx/edx-platform/blob/master/common/lib/xmodule/xmodule/video_module/video_module.py#L159) We wait a bit and see if YouTube responds. If not, then the switching to HTML5 happens. So that's 1.5 seconds. We wait for 3 second in the test to be completely sure that the switching finished.