public void setProviderInfos(List<ProviderInfo> providerInfos) {
        this.providerInfos = providerInfos;
    }
@Test
    public void setProviderInfos() throws Exception {
        ProviderGroup pg = new ProviderGroup("xxx", null);
        List list = pg.getProviderInfos();
        Assert.assertNotNull(list);
        Assert.assertTrue(list.size() == 0);

        List<ProviderInfo> newps = new ArrayList<ProviderInfo>();
        pg.setProviderInfos(newps);
        Assert.assertNotNull(list);
        Assert.assertTrue(list != pg.getProviderInfos());
        Assert.assertTrue(newps == pg.getProviderInfos());

        newps = Arrays.asList(ProviderHelper.toProviderInfo("127.0.0.1:12200"));
        pg.setProviderInfos(newps);
        Assert.assertNotNull(list);
        Assert.assertTrue(newps == pg.getProviderInfos());
        Assert.assertTrue(pg.getProviderInfos().size() == 1);
    }