List<DiagramElement> nodesToRemove = new ArrayList<DiagramElement>();
nodesToRemove.add((DiagramElement) mockNode1.proxy());
List<DiagramElement> connectionsToRemove = new ArrayList<DiagramElement>();
connectionsToRemove.add((DiagramElement) mockConnection.proxy());
removeNodeCommand = new DeleteElementCommand((DiagramEditorNotification)
mockNotification.proxy(), nodesToRemove);
removeConnectionCommand = new DeleteElementCommand(
(DiagramEditorNotification) mockNotification.proxy(),
connectionsToRemove);
connections.add((Connection) mockConnection.proxy());
}