*     the registry suffix section (labelled "ICANN").
   * @since 23.3
   */
  public boolean isRegistrySuffix() {
    return registrySuffixIndex() == 0;
  }

  /**
   * Indicates whether this domain name ends in a {@linkplain #isRegistrySuffix() registry suffix},
   * including if it is a registry suffix itself. For example, returns {@code true} for {@code

      assertFalse(name, domain.isRegistrySuffix());
      assertTrue(name, domain.hasRegistrySuffix());
      assertTrue(name, domain.isUnderRegistrySuffix());
    }
  }

  public void testUnderRegistrySuffix() {
    for (String name : SOMEWHERE_UNDER_RS) {
      InternetDomainName domain = InternetDomainName.from(name);
      assertFalse(name, domain.isRegistrySuffix());

      assertFalse(name, domain.isRegistrySuffix());
      assertTrue(name, domain.hasRegistrySuffix());
      assertTrue(name, domain.isUnderRegistrySuffix());
    }
  }

  public void testUnderRegistrySuffix() {
    for (String name : SOMEWHERE_UNDER_RS) {
      InternetDomainName domain = InternetDomainName.from(name);
      assertFalse(name, domain.isRegistrySuffix());