public void addVpls(VplsConfig vpls) {
        ObjectNode vplsNode = JsonNodeFactory.instance.objectNode();

        vplsNode.put(NAME, vpls.name());

        ArrayNode ifacesNode = vplsNode.putArray(INTERFACE);
        vpls.ifaces().forEach(ifacesNode::add);

        vplsNode.put(ENCAPSULATION, vpls.encap().toString());

        ArrayNode vplsArray = vplss().isEmpty() ?
                initVplsConfiguration() : (ArrayNode) object.get(VPLS);
        vplsArray.add(vplsNode);
    }
@Test
    public void addVpls() {
        int initialSize = vplsAppConfig.vplss().size();
        VplsConfig newVpls = createNewVpls();
        vplsAppConfig.addVpls(newVpls);
        assertEquals("The new VPLS has not been added correctly to the list of" +
                             "existing VPLSs",
                     initialSize + 1,
                     vplsAppConfig.vplss().size());
        vplss.add(newVpls);
    }