public List<HostAddress> toHostAddressList(Collection<Host> hosts)
    {
        ArrayList<HostAddress> list = new ArrayList<>(hosts.size());
        for (Host host : hosts) {
            list.add(toHostAddress(host));
        }
        return list;
    }
@Test
    public void testToHostAddressList()
            throws Exception
    {
        Set<Host> hosts = ImmutableSet.of(
                new TestHost(
                        new InetSocketAddress(
                                InetAddress.getByAddress(new byte[] {
                                        1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16
                                }),
                                3000)),
                new TestHost(new InetSocketAddress(InetAddress.getByAddress(new byte[] {1, 2, 3, 4}), 3000)));

        HostAddressFactory hostAddressFactory = new HostAddressFactory();
        List<HostAddress> list = hostAddressFactory.toHostAddressList(hosts);

        assertEquals(list.toString(), "[[102:304:506:708:90a:b0c:d0e:f10], 1.2.3.4]");
    }