Set<String> additions = new HashSet<String>();
additions.add("marketing manager");
additions.addAll(someAdditions);
actor.getGroupActorIds().addAll(additions);
assert actor.getGroupActorIds().size() == 3;
assert actor.clearDirty();
actor.getGroupActorIds().removeAll(additions);
assert actor.clearDirty();
assert actor.getGroupActorIds().size() == 0;
actor.getGroupActorIds().addAll(additions);