Mock implementation of the $animate service. Exposes two additional methods
for testing animations.
closeAndFlush();
This method will close all pending animations (both Javascript and CSS) and it will also flush any remaining animation frames and/or callbacks.
flush();
This method is used to flush the pending callbacks and animation frames to either start
an animation or conclude an animation. Note that this will not actually close an
actively running animation (see closeAndFlush() for that).