/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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 org.apache.commons.logging.log4j;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.commons.logging.DummyException;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import junit.framework.TestCase;
  
  /**
   * Abstract set of tests that can be executed with various classpaths set.
   * <p>
   * The tests verify that when running on a system with Log4J present,
   * Log4J is selected and that the logger basically works.
   */
  
  public abstract class StandardTests extends TestCase {
  
      /**
       * Simple structure to store information about messages that actually get
       * logged by the underlying logging library.
       */
      public static class LogEvent {
          public String msg;
          public String level;
          public Throwable throwable;
      }
  
      /**
       * Verify that the TestAppender has received the expected
       * number of messages. This assumes that:
       * <ul>
       * <li>setUpTestAppender has been called
       * <li>logPlainMessages or logExceptionMessages has been
       * called to log a known number of messages at known levels.
       * </ul>
       *
       * @param logEvents is the list of log events received.
       *
       * @param thrown False if logPlainMessages was called
       * (ie the TestAppender is expected to have received
       * logevents with no associated exception info). True if
       * logExceptionMessages was called.
       */
      private void checkLoggingEvents(final List logEvents, final boolean thrown) {
          LogEvent ev;
  
          assertEquals("Unexpected number of log events", 4, logEvents.size());
  
          ev = (LogEvent) logEvents.get(0);
          assertEquals("Info message expected", "info", ev.msg);
          assertEquals("Info level expected", "INFO", ev.level);
          assertEquals("Exception data incorrect", ev.throwable!=null, thrown);
  
          ev = (LogEvent) logEvents.get(1);
          assertEquals("Warn message expected", "warn", ev.msg);
          assertEquals("Warn level expected", "WARN", ev.level);
          assertEquals("Exception data incorrect", ev.throwable!=null, thrown);
  
          ev = (LogEvent) logEvents.get(2);
          assertEquals("Error message expected", "error", ev.msg);
          assertEquals("Error level expected", "ERROR", ev.level);
          assertEquals("Exception data incorrect", ev.throwable!=null, thrown);
  
          ev = (LogEvent) logEvents.get(3);
          assertEquals("Fatal message expected", "fatal", ev.msg);
          assertEquals("Fatal level expected", "FATAL", ev.level);
          assertEquals("Exception data incorrect", ev.throwable!=null, thrown);
      }
  
      /**
       * Log messages with exceptions
       */
      private void logExceptionMessages(final Log log) {
          final Throwable t = new DummyException();
          log.trace("trace", t); // Should not actually get logged
         log.debug("debug", t); // Should not actually get logged
         log.info("info", t);
         log.warn("warn", t);
         log.error("error", t);
         log.fatal("fatal", t);
     }
 
     /**
      * Log plain messages.
      */
     private void logPlainMessages(final Log log) {
         log.trace("trace"); // Should not actually get logged
         log.debug("debug"); // Should not actually get logged
         log.info("info");
         log.warn("warn");
         log.error("error");
         log.fatal("fatal");
     }
 
     /**
      * Sets up instance variables required by this test case.
      */
     @Override
     public void setUp() throws Exception {
         LogFactory.releaseAll();
     }
 
     /**
      * Modify Log4j's setup so that all messages actually logged get redirected
      * into the specified list.
      * <p>
      * This method also sets the logging level to INFO so that we
      * can test whether messages are getting properly filtered.
      */
     public abstract void setUpTestAppender(List logEvents) throws Exception;
 
     /**
      * Tear down instance variables required by this test case.
      */
     @Override
     public void tearDown() {
         LogFactory.releaseAll();
     }
 
     /**
      * Test that a LogFactory gets created as expected.
      */
     public void testCreateFactory() {
         final LogFactory factory = LogFactory.getFactory();
         assertNotNull("LogFactory exists", factory);
         assertEquals("LogFactory class", "org.apache.commons.logging.impl.LogFactoryImpl", factory.getClass().getName());
 
         final String[] names = factory.getAttributeNames();
         assertNotNull("Names exists", names);
         assertEquals("Names empty", 0, names.length);
     }
 
     /**
      * Verify that we can log exception messages.
      */
     public void testExceptionMessages() throws Exception {
         final List logEvents = new ArrayList();
         setUpTestAppender(logEvents);
         final Log log = LogFactory.getLog("test-category");
         logExceptionMessages(log);
         checkLoggingEvents(logEvents, true);
     }
 
     /**
      * Verify that we can log messages without exceptions.
      */
     public void testPlainMessages() throws Exception {
         final List logEvents = new ArrayList();
         setUpTestAppender(logEvents);
         final Log log = LogFactory.getLog("test-category");
         logPlainMessages(log);
         checkLoggingEvents(logEvents, false);
     }
 
     /**
      * Test Serializability of Log instance
      */
     public void testSerializable() throws Exception {
         final List logEvents = new ArrayList();
         setUpTestAppender(logEvents);
         final Log log = LogFactory.getLog("test-category");
 
         final ByteArrayOutputStream baos = new ByteArrayOutputStream();
         final ObjectOutputStream oos = new ObjectOutputStream(baos);
         oos.writeObject(log);
         oos.close();
         final ByteArrayInputStream bais =
             new ByteArrayInputStream(baos.toByteArray());
         final ObjectInputStream ois = new ObjectInputStream(bais);
         final Log newLog = (Log) ois.readObject();
         ois.close();
 
         // Check the characteristics of the resulting object
         logExceptionMessages(newLog);
         checkLoggingEvents(logEvents, true);
     }
 }