package org.djutils.test;
   
   import static org.junit.jupiter.api.Assertions.assertEquals;
   import static org.junit.jupiter.api.Assertions.assertNull;
   import static org.junit.jupiter.api.Assertions.assertTrue;
   import static org.junit.jupiter.api.Assertions.fail;
   
   import java.lang.reflect.Constructor;
   
  /**
   * ExceptionTest has a generic test method for testing an exception with four constructors.
   * <p>
   * Copyright (c) 2024-2025 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
   * for project information <a href="https://djutils.org" target="_blank"> https://djutils.org</a>. The DJUTILS project is
   * distributed under a three-clause BSD-style license, which can be found at
   * <a href="https://djutils.org/docs/license.html" target="_blank"> https://djutils.org/docs/license.html</a>.
   * </p>
   * @author <a href="https://www.tudelft.nl/averbraeck">Alexander Verbraeck</a>
   * @author <a href="https://www.github.com/WJSchakel">Wouter Schakel</a>
   */
  public final class ExceptionTest
  {
      /** */
      private ExceptionTest()
      {
          // utility class.
      }
      
      /**
       * Test exception class on constructors: empty, only message, only Throwable, message and Throwable.
       * @param clazz exception class to test.
       */
      public static void testExceptionClass(final Class<? extends Exception> clazz)
      {
          try
          {
              Constructor<? extends Exception> constructor = clazz.getConstructor();
              try
              {
                  throw constructor.newInstance();
              }
              catch (Exception e)
              {
                  checkRightException(e, clazz);
                  assertNull(e.getMessage());
              }
  
              constructor = clazz.getConstructor(String.class);
              try
              {
                  throw constructor.newInstance("abc");
              }
              catch (Exception e)
              {
                  checkRightException(e, clazz);
                  assertEquals("abc", e.getMessage());
              }
  
              constructor = clazz.getConstructor(Throwable.class);
              try
              {
                  throw constructor.newInstance(new IllegalArgumentException());
              }
              catch (Exception e)
              {
                  checkRightException(e, clazz);
                  assertTrue(e.getMessage().contains("IllegalArgumentException"));
                  assertTrue(e.getCause() instanceof IllegalArgumentException);
              }
  
              constructor = clazz.getConstructor(String.class, Throwable.class);
              try
              {
                  throw constructor.newInstance("abc", new IllegalArgumentException("def"));
              }
              catch (Exception e)
              {
                  checkRightException(e, clazz);
                  assertEquals("abc", e.getMessage());
                  assertTrue(e.getCause() instanceof IllegalArgumentException);
                  assertEquals("def", e.getCause().getMessage());
              }
          }
          catch (SecurityException | NoSuchMethodException ex)
          {
              fail("Class " + clazz + " is missing standard and accessible exception constructor.");
          }
      }
  
      /**
       * Test exception class type.
       * @param e thrown exception
       * @param clazz class of exception that should have been thrown
       */
      private static void checkRightException(final Exception e, final Class<? extends Exception> clazz)
      {
          if (!e.getClass().equals(clazz))
          {
              fail("Right exception not thrown. It is " + e.getClass().getSimpleName() + " instead of " + clazz.getSimpleName());
         }
     }
 }