Element: Add unit tests for focusin/focusout hack
Element: Add unit tests for focusin/focusout hack

Follows-up 33c379f.

Change-Id: I396093dfa813480df7b1675f366ace6ac8bf85b5

wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui