package com.atlassian.plugin.servlet.util;
   
   import junit.framework.TestCase;
   
   import java.net.URISyntaxException;
   
   public class TestClassLoaderStack extends TestCase
   {
       public void testThreadClassLoaderIsReplacedAndRestored() throws URISyntaxException
      {
          ClassLoader mainLoader = Thread.currentThread().getContextClassLoader();
          try
          {
              ClassLoader pluginLoader1 = new MockClassLoader();
              ClassLoader pluginLoader2 = new MockClassLoader();
  
              ClassLoaderStack.push(pluginLoader1);
              assertSame(pluginLoader1, Thread.currentThread().getContextClassLoader());
              ClassLoaderStack.push(pluginLoader2);
              assertSame(pluginLoader2, Thread.currentThread().getContextClassLoader());
              ClassLoaderStack.pop();
              assertSame(pluginLoader1, Thread.currentThread().getContextClassLoader());
              ClassLoaderStack.pop();
              assertSame(mainLoader, Thread.currentThread().getContextClassLoader());
          }
          finally
          {
              Thread.currentThread().setContextClassLoader(mainLoader);
          }
      }
  
      public void testPopReturnsPreviousContextClassLoader() throws Exception
      {
          ClassLoader mainLoader = Thread.currentThread().getContextClassLoader();
          try
          {
              ClassLoader pluginLoader1 = new MockClassLoader();
              ClassLoader pluginLoader2 = new MockClassLoader();
  
              ClassLoaderStack.push(pluginLoader1);
              assertSame(pluginLoader1, Thread.currentThread().getContextClassLoader());
              ClassLoaderStack.push(pluginLoader2);
              assertSame(pluginLoader2, Thread.currentThread().getContextClassLoader());
              ClassLoader previous = ClassLoaderStack.pop();
              assertSame(pluginLoader2, previous);
              assertSame(pluginLoader1, Thread.currentThread().getContextClassLoader());
              previous = ClassLoaderStack.pop();
              assertSame(pluginLoader1, previous);
              assertSame(mainLoader, Thread.currentThread().getContextClassLoader());
          }
          finally
          {
              // Clean up in case of error
              Thread.currentThread().setContextClassLoader(mainLoader);
          }
      }
  
      public void testPushAndPopHandleNull() throws Exception
      {
          ClassLoader mainLoader = Thread.currentThread().getContextClassLoader();
          try
          {
              // popping with empty stack should return null
              assertNull(ClassLoaderStack.pop());
              // pushing null should be a no-op
              ClassLoaderStack.push(null);
              assertSame(mainLoader, Thread.currentThread().getContextClassLoader());
              assertNull(ClassLoaderStack.pop());
          }
          finally
          {
              // Clean up in case of error
              Thread.currentThread().setContextClassLoader(mainLoader);
          }
      }
  
      public static class MockClassLoader extends ClassLoader
      {
      }
  }