assertFalse(IpAddressUtil.isIPv6Address("example.com"));

        // Null
        assertFalse(IpAddressUtil.isIPv6Address(null));
    }

    @Test
    public void testFormatForUrl() {
        // IPv6 addresses - should add brackets
        assertEquals("[::1]", IpAddressUtil.formatForUrl("::1"));
        assertEquals("[2001:db8::1]", IpAddressUtil.formatForUrl("2001:db8::1"));