@Override
    public Optional<ServiceInstance> choose(String serviceName) {
        return DiscoveryManager.INSTANCE.choose(serviceName);
    }
@Test
    public void choose() {
        final List<ServiceInstance> serviceInstances = mockInstances();
        final Optional<ServiceInstance> choose = lbService.choose(serviceName);
        Assert.assertTrue(choose.isPresent());
        Assert.assertTrue(serviceInstances.contains(choose.get()));
    }