Use protocol independent URLs whenever possible so that the browser will choose the protocol related to the protocol which the page is delivered with.
httpsand you provide a youtube video only via
httpthe most browsers (e.g. Firefox, Chrome) won't display the video.
https://youtu.be/jyElDp98HdIyour test which checks that the embeded video is rendered in the view will fail because your test server doesn't use https
Let your links look like
//youtu.be/jyElDp98HdI and you will be fine, server side and test side.