@Test
public void testInitializeDNSSuffix() {

    InstanceAWSProvider provider = new InstanceAWSProvider();
    System.clearProperty(InstanceAWSProvider.AWS_PROP_DNS_SUFFIX);
    provider.initialize("provider", "com.yahoo.athenz.instance.provider.impl.InstanceAWSProvider", null, null);
    assertNull(provider.dnsSuffix);
    provider.close();
    provider = new InstanceAWSProvider();
    System.setProperty(InstanceAWSProvider.AWS_PROP_DNS_SUFFIX, "");
    provider.initialize("provider", "com.yahoo.athenz.instance.provider.impl.InstanceAWSProvider", null, null);
    assertEquals("", provider.dnsSuffix);
    provider.close();
}