@Test
public void add() throws Exception {

    ProviderGroup pg = new ProviderGroup("xxx", null);
    Assert.assertTrue(pg.size() == 0);
    pg.add(null);
    Assert.assertTrue(pg.size() == 0);
    pg.add(ProviderHelper.toProviderInfo("127.0.0.1:12200"));
    Assert.assertTrue(pg.size() == 1);
    pg.add(ProviderHelper.toProviderInfo("127.0.0.1:12201"));
    Assert.assertTrue(pg.size() == 2);
    // 重复
    pg.add(ProviderHelper.toProviderInfo("127.0.0.1:12200"));
    Assert.assertTrue(pg.size() == 2);
}