Trigger an input's action from an acceptance test?

I've got this in my template:

{{input action="save" value=model.bar}}

The action is asynchronous. I would like to test that after a user edits the text field, the action is performed and the result is reflected on the page.

I tried this

fillIn('input', 'asdf');

and this

keyEvent('input', 'keypress', 13);

But neither triggers the action!

At the same time, doing click('button'); on a <button {{action "save"}}> does trigger the action.

How do i trigger an input's action from an acceptance test?

A fiddle: http://ift.tt/1E5JBia