@Test
    public void getAvailableClientTransport4() throws Exception {
        ConsumerConfig<HelloService> consumerConfig = new ConsumerConfig<HelloService>()
            .setInterfaceId(HelloService.class.getName())
            .setDirectUrl("bolt://127.0.0.1:22223,bolt://127.0.0.1:22224")
            .setConnectionHolder("all")
            .setRegister(false)
            .setLazy(true)
            .setTimeout(3000);
        HelloService helloService = consumerConfig.refer();
        ClientProxyInvoker invoker = (ClientProxyInvoker) ProxyFactory.getInvoker(helloService,
            consumerConfig.getProxy());
        Cluster cluster = invoker.getCluster();
        Assert.assertTrue(cluster.getConnectionHolder() instanceof AllConnectConnectionHolder);
        AllConnectConnectionHolder holder = (AllConnectConnectionHolder) cluster.getConnectionHolder();

        ProviderGroup providerGroups = new ProviderGroup();
        providerGroups.add(ProviderHelper.toProviderInfo("bolt://127.0.0.1:22223"));
        providerGroups.add(ProviderHelper.toProviderInfo("bolt://127.0.0.1:22224"));
        holder.updateProviders(providerGroups);
        Set<ProviderInfo> last = holder.currentProviderList();
        Assert.assertEquals(2, last.size());

        ProviderGroup providerGroups2 = new ProviderGroup();
        holder.updateProviders(providerGroups2);
        Set<ProviderInfo> current = holder.currentProviderList();

        Assert.assertEquals(0, current.size());

        consumerConfig.unRefer();
    }
@author <a href="mailto:zhanggeng.zg@antfin.com">GengZhang</a>
test/test-integration/src/test/java/com/alipay/sofa/rpc/test/client/AllConnectConnectionHolderTest.java