protected void configNeighbourHandler() {
        neighbourService.unregisterNeighbourHandlers(appId);
        interfaceService
                .getInterfaces()
                .forEach(intf -> neighbourService.registerNeighbourHandler(intf,
                                                                       neighbourHandler,
                                                                       appId));
    }
@Test
    public void testConfigNeighbourHandler() {
        vplsNeighbourHandler.configNeighbourHandler();
        assertEquals(9, vplsNeighbourHandler.neighbourService.getHandlerRegistrations().size());
    }