@Test
public void test_loadDnsCacheConfig_from_D_Option() throws Exception {

    final String key = "dcm.config.filename";
    System.setProperty(key, "customized-dns-cache.properties");
    DnsCacheManipulator.loadDnsCacheConfig();
    final String ip = InetAddress.getByName(DOMAIN_CUSTOMIZED).getHostAddress();
    assertEquals(IP_CUSTOMIZED, ip);
    System.clearProperty(key);
}