public static void refreshSuperUserGroupsConfiguration() {
    //load server side configuration;
    refreshSuperUserGroupsConfiguration(new Configuration());
  }
@Test
  public void testIPRange() {
    Configuration conf = new Configuration();
    conf.set(
        DefaultImpersonationProvider.getTestProvider().
            getProxySuperuserGroupConfKey(REAL_USER_NAME),
        "*");
    conf.set(
        DefaultImpersonationProvider.getTestProvider().
            getProxySuperuserIpConfKey(REAL_USER_NAME),
        PROXY_IP_RANGE);
    ProxyUsers.refreshSuperUserGroupsConfiguration(conf);

    // First try proxying a group that's allowed
    UserGroupInformation realUserUgi = UserGroupInformation
        .createRemoteUser(REAL_USER_NAME);
    UserGroupInformation proxyUserUgi = UserGroupInformation.createProxyUserForTesting(
        PROXY_USER_NAME, realUserUgi, GROUP_NAMES);

    // From good IP
    assertAuthorized(proxyUserUgi, "10.222.0.0");
    // From bad IP
    assertNotAuthorized(proxyUserUgi, "10.221.0.0");
  }