assertNull(IpAddressUtil.buildUrl(null, ipv4, 8080, "/path"));
        assertNull(IpAddressUtil.buildUrl("http", (InetAddress) null, 8080, "/path"));
    }

    @Test
    public void testBuildUrlWithHostString() {
        // IPv4 with port and path
        assertEquals("http://127.0.0.1:8080/path", IpAddressUtil.buildUrl("http", "127.0.0.1", 8080, "/path"));

        // IPv4 with port, no path