### Question:
Utils { public static String getStringIpAddress(IpAddress ipAddress) { if (ipAddress.getIpv4Address() != null) { return ipAddress.getIpv4Address().getValue(); } return ipAddress.getIpv6Address().getValue(); } private  Utils(); static IpPrefix createIpPrefix(String cidr); static IpAddress createIpAddress(String ipAddress); static String getStringIpPrefix(IpPrefix ipPrefix); static String getStringIpAddress(IpAddress ipAddress); static String normalizeUuid(String string); static void syncNat(ReadWriteTransaction rwTx, Floatingip oldFloatingIp, Floatingip newFloatingIp); static void removeNat(ReadWriteTransaction rwTx, Floatingip removedFloatingIp);  }### Answer:
@Test public final void testGetStringIpAddress_ipv4() { String ipv4Address = "1.1.1.1"; assertEquals(ipv4Address, Utils.getStringIpAddress(new IpAddress(new Ipv4Address(ipv4Address)))); }
@Test public final void testGetStringIpAddress_ipv6() { String ipv6Address = "2001:db8::211:22ff:fe33:4455"; assertEquals(ipv6Address, Utils.getStringIpAddress(new IpAddress(new Ipv6Address(ipv6Address)))); }
@Test public final void testGetStringIpAddress_null() { thrown.expect(NullPointerException.class); Utils.getStringIpAddress(null); }