assertTrue(newIPv4.isIPv4());
        assertFalse(newIPv4.isIPv6());
        assertEquals(WitnessNotification.WitnessIPAddress.IPV4, newIPv4.getFlags());

        // Check IPv6 address
        WitnessNotification.WitnessIPAddress newIPv6 = newAddresses.get(1);
        assertEquals(ipv6, newIPv6.getAddress());
        assertFalse(newIPv6.isIPv4());
        assertTrue(newIPv6.isIPv6());

        NetworkInterfaceInfo info = new NetworkInterfaceInfo(testAddress, 1000);

        assertEquals(testAddress, info.getAddress());
        assertEquals(1000, info.getLinkSpeed());
        assertFalse(info.isIpv6());
        assertEquals(0, info.getCapability());
    }

    @Test
    void testIPv6Constructor() throws UnknownHostException {
        InetAddress ipv6Address = InetAddress.getByName("2001:db8::1");

            return (flags & IPV4) != 0;
        }

        /**
         * Checks if this is an IPv6 address.
         *
         * @return true if IPv6
         */
        public boolean isIPv6() {
            return (flags & IPV6) != 0;
        }
    }

    /**
     * Adds a new IP address to the notification.
     *
     * @param address the new IP address
     */