### Question:
NetUtils { public static String toAddressString(InetSocketAddress address) { return address.getAddress().getHostAddress() + ":" + address.getPort(); }  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 testToAddressString() throws Exception { InetAddress address = mock(InetAddress.class); when(address.getHostAddress()).thenReturn("dubbo"); InetSocketAddress socketAddress = new InetSocketAddress(address, 1234); assertThat(NetUtils.toAddressString(socketAddress), equalTo("dubbo:1234")); }