Testing Castbar.Shield
 

Are there any convenient mobs that cast no-interrupt spells that can be used to test this? (I asked on the WoW forums too, but I think people here are more likely to understand the question.)

All I can think to do is keep resetting Kael'thas in Magister's Terrace, but surely there's something more accessible!

Hi. You can set target or focus on yourself, and try to cast any mount spell. In my setup it triggers shield icon.

It doesn't work for me, but that could easily be my own problem.

Which mod are you using for the display? I'll try it and see how it works.

edit: Someone found me http://www.wowhead.com/npc=43341 where Steady Shot puts up the shield.

edit: Hearthstone / Mount works on some characters but not others, and it's not addon-related as far as I can tell. Even just doing /dump select(9,UnitCastingInfo("target")) will return true for Hearthstone on my mage, but not my druid.

Maybe it's a cVar? Oh well, pretty weird.