Since you can't see how much damage is taken on e-shield, I would think you need to use time for comparison. The easiest way to test this out (in my mind, anyway) would be to head to the arena/duel with a Druid. Have stopwatch or a clock with second hand available.
My initial thought would be to do as follows.
Test 1: Mage strips down, removing all items that give regen, resits, or anything else. Mage casts e-shield. Druid attacks and only uses auto Totem in the attack. Note the time until e-shield expires. Druid kills the Mage to end the test.
Heal up.
Test 2: Druid casts Bark on the Mage, and Mage casts e-shield on him/herself. (Note that if performing tests in the arena, you will need to go into the hallway to cast Bark). Druid auto attacks using only Totem. Note the time until e-shield expires. Druid kills the Mage to end the test.
Heal up.
Test 3: Druid casts Bark on the Mage, Mage casts e-shield. Druid attacks using a combination of Totem melee, and skills such as Vines, Lightning, and Storm, if possible. Note the time until e-shield expires. Druid kills Mage to end the test.
Heal up.
Test 4: Mage puts on his/her normal attire, which would hopefully be giving resists. Mage casts e-shield, Druid attacks using only Totem auto attack. Note time until e-shield expires. Druid kills Mage.
Heal up.
Test 5: Mage wearing armor, Druid casts Bark, Mage casts e-shield. Druid attacks using only auto Totem. Note time, Druid kills.
Heal up.
Test 6: Same as Test 5, but Druid attacks using melee and skills. Note time. Mage kills Druid to get back at him for the 5 prior deaths.
All tests should try to be consistent in attack times. ie. If you put up e-shield and immediately start the auto attack in Test 1, don't put up e-shield in the hall and then run to the arena for Test 2. E-shield, attack.
I would expect that having Bark/armor would allow you to take less melee damage, as Bark doesn't matter against magic. It should, in theory. I should note that I really have no idea how e-shield works, however, and am only commenting on an invite from Mariner. The way I think it works is that it is on a timer... but it can expire early if enough melee damage is taken. Is that correct?
I will also admit that there is no real reason for the Druid to kill the Mage to end each test, other than it is the only way that a Druid could beat a Mage. Well, to search for a reason I could say that the Bark buff would end upon death. But no... I just want to see a Druid kill the Mage.
