content: /*
   * Copyright (C) 2011 Clearspring Technologies, Inc. 
   *
   * 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.clearspring.analytics.util;
  
  import java.util.ConcurrentModificationException;
  
  import org.junit.Test;
  
  import static org.junit.Assert.assertArrayEquals;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertNull;
  import static org.junit.Assert.assertTrue;
  import static org.junit.Assert.fail;
  
  public class TestDoublyLinkedList {
  
      @Test
      public void testDoublyLinkedList() {
          DoublyLinkedList<Integer> list = new DoublyLinkedList<Integer>();
          assertIsEmpty(list);
      }
  
      @Test
      public void testAdd() {
          DoublyLinkedList<Integer> list = new DoublyLinkedList<Integer>();
          list.add(1);
          assertFalse(list.isEmpty());
          assertEquals(1, list.size());
          assertArrayEquals(new Integer[]{1}, list.toArray());
          list.add(2);
          assertFalse(list.isEmpty());
          assertEquals(2, list.size());
          assertArrayEquals(new Integer[]{1, 2}, list.toArray());
          list.add(3);
          assertFalse(list.isEmpty());
          assertEquals(3, list.size());
          assertArrayEquals(new Integer[]{1, 2, 3}, list.toArray());
          assertEquals(new Integer(1), list.first());
      }
  
      @Test
      public void testEnqueue() {
          DoublyLinkedList<Integer> list = new DoublyLinkedList<Integer>();
          list.enqueue(1);
          assertFalse(list.isEmpty());
          assertEquals(1, list.size());
          assertArrayEquals(new Integer[]{1}, list.toArray());
          list.enqueue(2);
          assertFalse(list.isEmpty());
          assertEquals(2, list.size());
          assertArrayEquals(new Integer[]{2, 1}, list.toArray());
          list.enqueue(3);
          assertFalse(list.isEmpty());
          assertEquals(3, list.size());
          assertArrayEquals(new Integer[]{3, 2, 1}, list.toArray());
          assertEquals(new Integer(3), list.first());
          assertEquals(new Integer(1), list.last());
      }
  
      @Test
      public void testAddNode() {
          DoublyLinkedList<Integer> list = new DoublyLinkedList<Integer>();
          list.add(new ListNode2<Integer>(1));
          assertFalse(list.isEmpty());
          assertEquals(1, list.size());
          assertArrayEquals(new Integer[]{1}, list.toArray());
          list.add(new ListNode2<Integer>(2));
          assertFalse(list.isEmpty());
          assertEquals(2, list.size());
          assertArrayEquals(new Integer[]{1, 2}, list.toArray());
          list.add(new ListNode2<Integer>(3));
          assertFalse(list.isEmpty());
          assertEquals(3, list.size());
          assertArrayEquals(new Integer[]{1, 2, 3}, list.toArray());
          assertEquals(new Integer(1), list.first());
      }
  
      @Test
      public void testAddAfter() {
          DoublyLinkedList<Integer> list = new DoublyLinkedList<Integer>();
          list.add(1);
          ListNode2<Integer> node2 = list.add(2);
          ListNode2<Integer> node4 = list.add(4);
  
          list.addAfter(node2, 3);
          assertEquals(4, list.size());
          assertArrayEquals(new Integer[]{1, 2, 3, 4}, list.toArray());
  
          ListNode2<Integer> node5 = list.addAfter(node4, 5);
          assertEquals(5, list.size());
          assertArrayEquals(new Integer[]{1, 2, 3, 4, 5}, list.toArray());
          assertEquals(new Integer(5), list.last());
          assertEquals(node5, list.head());
      }
  
      @Test
      public void testRemove() {
          DoublyLinkedList<Integer> list = new DoublyLinkedList<Integer>();
          ListNode2<Integer> node1 = list.add(1);
          list.remove(node1);
  
          node1 = list.add(1);
          ListNode2<Integer> node2 = list.add(2);
          list.remove(node1);
          assertEquals(1, list.size());
          assertEquals(new Integer(2), list.first());
          assertEquals(node2, list.head());
          assertArrayEquals(new Integer[]{2}, list.toArray());
          list.remove(node2);
          assertIsEmpty(list);
  
          node1 = list.add(1);
          node2 = list.add(2);
          list.remove(node2);
          assertEquals(1, list.size());
          assertEquals(new Integer(1), list.first());
          assertEquals(node1, list.head());
          assertArrayEquals(new Integer[]{1}, list.toArray());
  
          node2 = list.add(2);
          list.add(3);
          assertEquals(3, list.size());
          assertArrayEquals(new Integer[]{1, 2, 3}, list.toArray());
          list.remove(node2);
          assertEquals(2, list.size());
          assertEquals(node1, list.tail());
          assertEquals(new Integer(3), list.last());
          assertArrayEquals(new Integer[]{1, 3}, list.toArray());
      }
  
      @Test(expected = ConcurrentModificationException.class)
      public void testConcurrentModification() {
          DoublyLinkedList<Integer> list = new DoublyLinkedList<Integer>();
          list.add(1);
          list.add(2);
          list.add(3);
  
          for (int i : list) {
              if (i == 2) {
                  list.add(4);
              }
          }
      }
  
      private <T> void assertIsEmpty(DoublyLinkedList<T> list) {
          assertNull(list.tail());
          assertNull(list.head());
          assertNull(list.first());
          assertNull(list.last());
          assertTrue(list.isEmpty());
          assertEquals(0, list.size());
          for (T i : list) {
              fail("What is this: " + i + " ?");
          }
      }
  
  }
  