mergedNodes.add(new Node(11));
mergedNodes.add(new Node(12));
mergedNodes.add(new Node(13));
mergedNodes.add(new Node(14));
model.moveDownMerged(new int[]{1,2,3});
assertEquals(5, mergedNodes.size());
assertEquals(10, mergedNodes.get(0).getId());
assertEquals(14, mergedNodes.get(1).getId());
assertEquals(11, mergedNodes.get(2).getId());