content: /*
   * Copyright 1999-2020 Alibaba Group Holding Ltd.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.alibaba.nacos.api.utils;
  
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.Test;
  
  import java.lang.reflect.Field;
  import java.lang.reflect.Method;
  import java.net.InetAddress;
  import java.util.Properties;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.mockito.Mockito.mock;
  import static org.mockito.Mockito.when;
  
  class NetUtilsTest {
      
      @AfterEach
      void tearDown() throws Exception {
          Class<?> clazz = Class.forName("com.alibaba.nacos.api.utils.NetUtils");
          Field field = clazz.getDeclaredField("localIp");
          field.setAccessible(true);
          field.set(null, "");
          System.clearProperty("com.alibaba.nacos.client.local.ip");
          System.clearProperty("com.alibaba.nacos.client.local.preferHostname");
          System.clearProperty("java.net.preferIPv6Addresses");
      }
      
      @Test
      void testLocalIpWithSpecifiedIp() {
          System.setProperty("com.alibaba.nacos.client.local.ip", "10.2.8.8");
          assertEquals("10.2.8.8", NetUtils.localIp());
          System.setProperty("com.alibaba.nacos.client.local.ip", "10.2.8.9");
          assertEquals("10.2.8.8", NetUtils.localIp());
      }
      
      @Test
      void testLocalIpWithPreferHostname() throws Exception {
          InetAddress inetAddress = invokeGetInetAddress();
          String hostname = inetAddress.getHostName();
          System.setProperty("com.alibaba.nacos.client.local.preferHostname", "true");
          assertEquals(hostname, NetUtils.localIp());
      }
      
      @Test
      void testLocalIpWithoutPreferHostname() throws Exception {
          InetAddress inetAddress = invokeGetInetAddress();
          String ip = inetAddress.getHostAddress();
          assertEquals(ip, NetUtils.localIp());
      }
      
      @Test
      void testLocalIpWithException() throws Exception {
          Field field = System.class.getDeclaredField("props");
          field.setAccessible(true);
          Properties properties = (Properties) field.get(null);
          Properties mockProperties = mock(Properties.class);
          when(mockProperties.getProperty("java.net.preferIPv6Addresses")).thenThrow(new RuntimeException("test"));
          field.set(null, mockProperties);
          try {
              System.setProperty("java.net.preferIPv6Addresses", "aaa");
              InetAddress expect = InetAddress.getLocalHost();
              assertEquals(expect.getHostAddress(), NetUtils.localIp());
          } finally {
              field.set(null, properties);
          }
      }
      
      private InetAddress invokeGetInetAddress() throws Exception {
          Class<?> clazz = Class.forName("com.alibaba.nacos.api.utils.NetUtils");
          Method method = clazz.getDeclaredMethod("findFirstNonLoopbackAddress");
          method.setAccessible(true);
          return (InetAddress) method.invoke(null);
      }
      
  }
  