### Question:
NetUtils { public static String toURL(String protocol, String host, int port, String path) { StringBuilder sb = new StringBuilder(); sb.append(protocol).append(": sb.append(host).append(':').append(port); if (path.charAt(0) != '/') { sb.append('/'); } sb.append(path); return sb.toString(); }  static int getRandomPort(); static int getAvailablePort(); static int getAvailablePort(int port); static boolean isInvalidPort(int port); static boolean isValidAddress(String address); static boolean isLocalHost(String host); static boolean isAnyHost(String host); static boolean isInvalidLocalHost(String host); static boolean isValidLocalHost(String host); static InetSocketAddress getLocalSocketAddress(String host, int port); static String getLocalHost(); static String filterLocalHost(String host); static InetAddress getLocalAddress(); static String getHostName(String address); static String getIpByHost(String hostName); static String toAddressString(InetSocketAddress address); static InetSocketAddress toAddress(String address); static String toURL(String protocol, String host, int port, String path);  }### Answer:
@Test public void testToURL() throws Exception { String url = NetUtils.toURL("dubbo", "host", 1234, "foo"); assertThat(url, equalTo("dubbo: }