@Test
public void testGetFullyQualifiedEmailAddressesDefaultUserDomain() {

    System.setProperty("athenz.notification_email_domain_from", "from.test.com");
    System.setProperty("athenz.notification_email_domain_to", "test.com");
    Set<String> recipients = new HashSet<>(Arrays.asList("user.user1", "user.user2", "user.user3"));
    NotificationToEmailConverterCommon notificationToEmailConverterCommon = new NotificationToEmailConverterCommon();
    Set<String> recipientsResp = notificationToEmailConverterCommon.getFullyQualifiedEmailAddresses(recipients);
    assertNotNull(recipientsResp);
    assertEquals(recipientsResp.size(), 3);
    assertTrue(recipientsResp.contains("user1@test.com"));
    assertTrue(recipientsResp.contains("user2@test.com"));
    assertTrue(recipientsResp.contains("user3@test.com"));
    System.clearProperty("athenz.notification_email_domain_from");
    System.clearProperty("athenz.notification_email_domain_to");
}