Testing a JQuery-UI Drag and Drop using WebTest

Just a quick post regarding using WebTest with JQuery-UI Draggable and Droppable.
The way that WebTest performs a drag and drop is as follows:

from.mouseDown()
to.mouseOver()
to.mouseUp()

Note that there is no intermediate move events between mouse down on the thing you're dragging and mousing over the target element.
What this means is that you need to configure your Draggable to start dragging on mousedown without delay. You can do this by setting the distance and delay options to zero (delay is zero by default):

$('.block').draggable({distance:0});

WebTest will now be able to click and drag it correctly. Unfortunately due to HtmlUnits 'renderless' behaviour you cannot specify exactly where you want to drop it so if you require precise targeting to properly test your application you're out of luck.