@Override
    public Map<String, String> getMetadata(Server server) {
        if (server instanceof ServiceCombServer) {
            return ((ServiceCombServer) server).getMetadata();
        }
        return super.getMetadata(server);
    }
@Test
    public void getMetadata() {
        final ServiceCombServerIntrospector introspector = new ServiceCombServerIntrospector();
        final Map<String, String> metadata = introspector.getMetadata(new Server("localhost:9090"));
        Assert.assertEquals(metadata, Collections.emptyMap());
        final ServiceCombServer serviceCombServer = Mockito.mock(ServiceCombServer.class);
        final HashMap<String, String> meta = new HashMap<>();
        Mockito.when(serviceCombServer.getMetadata()).thenReturn(meta);
        assertEquals(introspector.getMetadata(serviceCombServer), meta);
    }