/*
    * 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.collections4.list;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.io.IOException;
  import java.io.Serializable;
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.util.AbstractCollection;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.ConcurrentModificationException;
  import java.util.Iterator;
  import java.util.List;
  import java.util.ListIterator;
  import java.util.NoSuchElementException;
  
  import org.apache.commons.collections4.BulkTest;
  import org.apache.commons.collections4.collection.AbstractCollectionTest;
  import org.apache.commons.collections4.iterators.AbstractListIteratorTest;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests {@link java.util.List}.
   * <p>
   * To use, simply extend this class, and implement
   * the {@link #makeObject} method.
   * </p>
   * <p>
   * If your {@link List} fails one of these tests by design,
   * you may still use this base set of cases.  Simply override the
   * test case (method) your {@link List} fails or override one of the
   * protected methods from AbstractCollectionTest.
   * </p>
   *
   * @param <E> the type of elements returned by this iterator
   */
  public abstract class AbstractListTest<E> extends AbstractCollectionTest<E> {
  
      public static class BulkTestSubList<E> extends AbstractListTest<E> {
  
          private final AbstractListTest<E> outer;
  
          public BulkTestSubList(final AbstractListTest<E> outer) {
              this.outer = outer;
          }
  
          @Override
          @SuppressWarnings("unchecked")
          public E[] getFullElements() {
              final List<E> l = Arrays.asList(outer.getFullElements());
              return (E[]) l.subList(3, l.size() - 3).toArray();
          }
  
          @Override
          public E[] getOtherElements() {
              return outer.getOtherElements();
          }
  
          @Override
          public boolean isAddSupported() {
              return outer.isAddSupported();
          }
  
          @Override
          public boolean isRemoveSupported() {
              return outer.isRemoveSupported();
          }
  
          @Override
          public boolean isSetSupported() {
              return outer.isSetSupported();
          }
  
          @Override
          public boolean isTestSerialization() {
              return false;
          }
 
         @Override
         public List<E> makeFullCollection() {
             final int size = getFullElements().length;
             return outer.makeFullCollection().subList(3, size - 3);
         }
 
         @Override
         public List<E> makeObject() {
             return outer.makeFullCollection().subList(4, 4);
         }
 
         @Override
         public void resetEmpty() {
             outer.resetFull();
             setCollection(outer.getCollection().subList(4, 4));
             setConfirmed(outer.getConfirmed().subList(4, 4));
         }
 
         @Override
         public void resetFull() {
             outer.resetFull();
             final int size = outer.getConfirmed().size();
             setCollection(outer.getCollection().subList(3, size - 3));
             setConfirmed(outer.getConfirmed().subList(3, size - 3));
         }
 
         @Override
         public void verify() {
             super.verify();
             outer.verify();
         }
     }
 
     public class TestListIterator extends AbstractListIteratorTest<E> {
 
         @Override
         public E addSetValue() {
             return getOtherElements()[0];
         }
 
         @Override
         public ListIterator<E> makeEmptyIterator() {
             resetEmpty();
             return AbstractListTest.this.getCollection().listIterator();
         }
 
         @Override
         public ListIterator<E> makeObject() {
             resetFull();
             return AbstractListTest.this.getCollection().listIterator();
         }
 
         @Override
         public boolean supportsAdd() {
             return isAddSupported();
         }
 
         @Override
         public boolean supportsRemove() {
             return isRemoveSupported();
         }
 
         @Override
         public boolean supportsSet() {
             return AbstractListTest.this.isSetSupported();
         }
     }
 
     /**
      *  Traverses to the beginning of the given iterator.
      *
      *  @param iter  the iterator to traverse
      *  @param i     the starting index
      */
     private void backwardTest(final ListIterator<E> iter, int i) {
         final List<E> list = getCollection();
 
         while (i > 0) {
             assertTrue(iter.hasPrevious(),
                 "Iterator should have previous, i:" + i);
             assertEquals(i, iter.nextIndex(),
                 "Iterator.nextIndex should work, i:" + i);
             assertEquals(i - 1, iter.previousIndex(),
                 "Iterator.previousIndex should work, i:" + i);
             final E o = iter.previous();
             assertEquals(list.get(i - 1), o,
                 "Iterator returned correct element");
             i--;
         }
 
         assertFalse(iter.hasPrevious(), "Iterator shouldn't have previous");
         final int nextIndex = iter.nextIndex();
         assertEquals(0, nextIndex, "nextIndex should be 0");
         final int prevIndex = iter.previousIndex();
         assertEquals(-1, prevIndex, "previousIndex should be -1");
 
         assertThrows(NoSuchElementException.class, () -> iter.previous(),
                 "Exhausted iterator should raise NoSuchElement");
     }
 
     public BulkTest bulkTestListIterator() {
         return new TestListIterator();
     }
 
     /**
      *  Returns a {@link BulkTest} for testing {@link List#subList(int,int)}.
      *  The returned bulk test will run through every {@code TestList}
      *  method, <em>including</em> another {@code bulkTestSubList}.
      *  Sublists are tested until the size of the sublist is less than 10.
      *  Each sublist is 6 elements smaller than its parent list.
      *  (By default this means that two rounds of sublists will be tested).
      *  The verify() method is overloaded to test that the original list is
      *  modified when the sublist is.
      */
     public BulkTest bulkTestSubList() {
         if (getFullElements().length - 6 < 10) {
             return null;
         }
         return new BulkTestSubList<>(this);
     }
 
     /**
      * Invokes all the methods on the given sublist to make sure they raise
      * a {@link java.util.ConcurrentModificationException ConcurrentModificationException}.
      */
     protected void failFastAll(final List<E> list) {
         final Method[] methods = List.class.getMethods();
         for (final Method method : methods) {
             failFastMethod(list, method);
         }
     }
 
     /**
      * Invokes the given method on the given sublist to make sure it raises
      * a {@link java.util.ConcurrentModificationException ConcurrentModificationException}.
      *
      * Unless the method happens to be the equals() method, in which case
      * the test is skipped. There seems to be a bug in
      * java.util.AbstractList.subList(int,int).equals(Object) -- it never
      * raises a ConcurrentModificationException.
      *
      * @param list the sublist to test
      * @param m the method to invoke
      */
     protected void failFastMethod(final List<E> list, final Method m) {
         if (m.getName().equals("equals")) {
             return;
         }
 
         final E element = getOtherElements()[0];
         final Collection<E> c = Collections.singleton(element);
 
         final Class<?>[] types = m.getParameterTypes();
         final Object[] params = new Object[types.length];
         for (int i = 0; i < params.length; i++) {
             if (types[i] == Integer.TYPE) {
                 params[i] = Integer.valueOf(0);
             } else if (types[i] == Collection.class) {
                 params[i] = c;
             } else if (types[i] == Object.class) {
                 params[i] = element;
             } else if (types[i] == Object[].class) {
                 params[i] = new Object[0];
             }
         }
 
         final InvocationTargetException thrown = assertThrows(InvocationTargetException.class, () -> m.invoke(list, params),
                 m.getName() + " should raise ConcurrentModification");
         assertTrue(thrown.getTargetException() instanceof ConcurrentModificationException,
                 m.getName() + " raised unexpected " + thrown.getTargetException());
     }
 
     /**
      *  Traverses to the end of the given iterator.
      *
      *  @param iter  the iterator to traverse
      *  @param i     the starting index
      */
     private void forwardTest(final ListIterator<E> iter, int i) {
         final List<E> list = getCollection();
         final int max = getFullElements().length;
 
         while (i < max) {
             assertTrue(iter.hasNext(), "Iterator should have next");
             assertEquals(i, iter.nextIndex(),
                 "Iterator.nextIndex should work");
             assertEquals(i - 1, iter.previousIndex(),
                 "Iterator.previousIndex should work");
             final Object o = iter.next();
             assertEquals(list.get(i), o, "Iterator returned correct element");
             i++;
         }
 
         assertFalse(iter.hasNext(), "Iterator shouldn't have next");
         assertEquals(max, iter.nextIndex(), "nextIndex should be size");
         assertEquals(max - 1, iter.previousIndex(), "previousIndex should be size - 1");
 
         assertThrows(NoSuchElementException.class, () -> iter.next(),
                 "Exhausted iterator should raise NoSuchElement");
     }
 
     /**
      * Returns the {@link #collection} field cast to a {@link List}.
      *
      * @return the collection field as a List
      */
     @Override
     public List<E> getCollection() {
         return (List<E>) super.getCollection();
     }
 
     /**
      * Returns the {@link #confirmed} field cast to a {@link List}.
      *
      * @return the confirmed field as a List
      */
     @Override
     public List<E> getConfirmed() {
         return (List<E>) super.getConfirmed();
     }
 
     /**
      * List equals method is defined.
      */
     @Override
     public boolean isEqualsCheckable() {
         return true;
     }
 
     /**
      *  Returns true if the collections produced by
      *  {@link #makeObject()} and {@link #makeFullCollection()}
      *  support the <code>set operation.<p>
      *  Default implementation returns true.  Override if your collection
      *  class does not support set.
      */
     public boolean isSetSupported() {
         return true;
     }
 
     /**
      * Returns an empty {@link ArrayList}.
      */
     @Override
     public Collection<E> makeConfirmedCollection() {
         return new ArrayList<>();
     }
 
     /**
      * Returns a full {@link ArrayList}.
      */
     @Override
     public Collection<E> makeConfirmedFullCollection() {
         return new ArrayList<>(Arrays.asList(getFullElements()));
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public List<E> makeFullCollection() {
         // only works if list supports optional "addAll(Collection)"
         final List<E> list = makeObject();
         list.addAll(Arrays.asList(getFullElements()));
         return list;
     }
 
     /**
      * Returns {@link #makeObject()}.
      *
      * @return an empty list to be used for testing
      */
     @Override
     public abstract List<E> makeObject();
 
     /**
      * Compare the current serialized form of the List
      * against the canonical version in SCM.
      */
     @Test
     @SuppressWarnings("unchecked")
     public void testEmptyListCompatibility() throws IOException, ClassNotFoundException {
         /*
          * Create canonical objects with this code
         List list = makeEmptyList();
         if (!(list instanceof Serializable)) return;
 
         writeExternalFormToDisk((Serializable) list, getCanonicalEmptyCollectionName(list));
         */
 
         // test to make sure the canonical form has been preserved
         final List<E> list = makeObject();
         if (list instanceof Serializable && !skipSerializedCanonicalTests()
                 && isTestSerialization()) {
             final List<E> list2 = (List<E>) readExternalFormFromDisk(getCanonicalEmptyCollectionName(list));
             assertEquals(0, list2.size(), "List is empty");
             assertEquals(list, list2);
         }
     }
 
     @Test
     @SuppressWarnings("unchecked")
     public void testEmptyListSerialization() throws IOException, ClassNotFoundException {
         final List<E> list = makeObject();
         if (!(list instanceof Serializable && isTestSerialization())) {
             return;
         }
 
         final byte[] object = writeExternalFormToBytes((Serializable) list);
         final List<E> list2 = (List<E>) readExternalFormFromBytes(object);
 
         assertEquals(0, list.size(), "Both lists are empty");
         assertEquals(0, list2.size(), "Both lists are empty");
     }
 
     /**
      * Compare the current serialized form of the List
      * against the canonical version in SCM.
      */
     @Test
     @SuppressWarnings("unchecked")
     public void testFullListCompatibility() throws IOException, ClassNotFoundException {
         /*
          * Create canonical objects with this code
         List list = makeFullList();
         if (!(list instanceof Serializable)) return;
 
         writeExternalFormToDisk((Serializable) list, getCanonicalFullCollectionName(list));
         */
 
         // test to make sure the canonical form has been preserved
         final List<E> list = makeFullCollection();
         if (list instanceof Serializable && !skipSerializedCanonicalTests() && isTestSerialization()) {
             final List<E> list2 = (List<E>) readExternalFormFromDisk(getCanonicalFullCollectionName(list));
             if (list2.size() == 4) {
                 // old serialized tests
                 return;
             }
             assertEquals(list.size(), list2.size(), "List is the right size");
             assertEquals(list, list2);
         }
     }
 
     @Test
     @SuppressWarnings("unchecked")
     public void testFullListSerialization() throws IOException, ClassNotFoundException {
         final List<E> list = makeFullCollection();
         final int size = getFullElements().length;
         if (!(list instanceof Serializable && isTestSerialization())) {
             return;
         }
 
         final byte[] object = writeExternalFormToBytes((Serializable) list);
         final List<E> list2 = (List<E>) readExternalFormFromBytes(object);
 
         assertEquals(size, list.size(), "Both lists are same size");
         assertEquals(size, list2.size(), "Both lists are same size");
     }
 
     /**
      *  Tests {@link List#add(int,Object)}.
      */
     @Test
     public void testListAddByIndex() {
         if (!isAddSupported()) {
             return;
         }
 
         final E element = getOtherElements()[0];
         final int max = getFullElements().length;
 
         for (int i = 0; i <= max; i++) {
             resetFull();
             getCollection().add(i, element);
             getConfirmed().add(i, element);
             verify();
         }
     }
 
     /**
      *  Tests bounds checking for {@link List#add(int, Object)} on an
      *  empty list.
      */
     @Test
     public void testListAddByIndexBoundsChecking() {
         if (!isAddSupported()) {
             return;
         }
 
         final E element = getOtherElements()[0];
 
         final List<E> finalList0 = makeObject();
         assertThrows(IndexOutOfBoundsException.class, () -> finalList0.add(Integer.MIN_VALUE, element),
                 "List.add should throw IndexOutOfBoundsException [Integer.MIN_VALUE]");
 
         final List<E> finalList1 = makeObject();
         assertThrows(IndexOutOfBoundsException.class, () -> finalList1.add(-1, element),
                 "List.add should throw IndexOutOfBoundsException [-1]");
 
         final List<E> finalList2 = makeObject();
         assertThrows(IndexOutOfBoundsException.class, () -> finalList2.add(1, element),
                 "List.add should throw IndexOutOfBoundsException [1]");
 
         final List<E> finalList3 = makeObject();
         assertThrows(IndexOutOfBoundsException.class, () -> finalList3.add(Integer.MAX_VALUE, element),
                 "List.add should throw IndexOutOfBoundsException [Integer.MAX_VALUE]");
     }
 
     /**
      *  Tests bounds checking for {@link List#add(int, Object)} on a
      *  full list.
      */
     @Test
     public void testListAddByIndexBoundsChecking2() {
         if (!isAddSupported()) {
             return;
         }
 
         final E element = getOtherElements()[0];
 
         final List<E> finalList0 = makeFullCollection();
         assertThrows(IndexOutOfBoundsException.class, () -> finalList0.add(Integer.MIN_VALUE, element),
                 "List.add should throw IndexOutOfBoundsException [Integer.MIN_VALUE]");
 
         final List<E> finalList1 = makeFullCollection();
         assertThrows(IndexOutOfBoundsException.class, () -> finalList1.add(-1, element),
                 "List.add should throw IndexOutOfBoundsException [-1]");
 
         final List<E> finalList2 = makeFullCollection();
         assertThrows(IndexOutOfBoundsException.class, () -> finalList2.add(finalList2.size() + 1, element),
                 "List.add should throw IndexOutOfBoundsException [size + 1]");
 
         final List<E> finalList3 = makeFullCollection();
         assertThrows(IndexOutOfBoundsException.class, () -> finalList3.add(Integer.MAX_VALUE, element),
                 "List.add should throw IndexOutOfBoundsException [Integer.MAX_VALUE]");
     }
 
     /**
      *  Tests {@link List#equals(Object)}.
      */
     @Test
     public void testListEquals() {
         resetEmpty();
         List<E> list = getCollection();
         assertTrue(list.equals(getConfirmed()), "Empty lists should be equal");
         verify();
         assertTrue(list.equals(list), "Empty list should equal self");
         verify();
 
         List<E> list2 = Arrays.asList(getFullElements());
         assertFalse(list.equals(list2), "Empty list shouldn't equal full");
         verify();
 
         list2 = Arrays.asList(getOtherElements());
         assertFalse(list.equals(list2), "Empty list shouldn't equal other");
         verify();
 
         resetFull();
         list = getCollection();
         assertTrue(list.equals(getConfirmed()), "Full lists should be equal");
         verify();
         assertTrue(list.equals(list), "Full list should equal self");
         verify();
 
         list2 = makeObject();
         assertFalse(list.equals(list2), "Full list shouldn't equal empty");
         verify();
 
         list2 = Arrays.asList(getOtherElements());
         assertFalse(list.equals(list2), "Full list shouldn't equal other");
         verify();
 
         list2 = Arrays.asList(getFullElements());
         if (list2.size() < 2 && isAddSupported()) {
             // main list is only size 1, so let's add other elements to get a better list
             list.addAll(Arrays.asList(getOtherElements()));
             getConfirmed().addAll(Arrays.asList(getOtherElements()));
             list2 = new ArrayList<>(list2);
             list2.addAll(Arrays.asList(getOtherElements()));
         }
         if (list2.size() > 1) {
             Collections.reverse(list2);
             assertFalse(list.equals(list2), "Full list shouldn't equal full list with same elements but different order");
             verify();
         }
 
         resetFull();
         list = getCollection();
         assertFalse(list.isEmpty(), "List shouldn't equal String");
         verify();
 
         final List<E> listForC = Arrays.asList(getFullElements());
         final Collection<E> c = new AbstractCollection<E>() {
             @Override
             public Iterator<E> iterator() {
                 return listForC.iterator();
             }
 
             @Override
             public int size() {
                 return listForC.size();
             }
         };
 
         assertFalse(list.equals(c), "List shouldn't equal nonlist with same elements in same order");
         verify();
     }
 
     /**
      *  Tests {@link List#get(int)}.
      */
     @Test
     public void testListGetByIndex() {
         resetFull();
         final List<E> list = getCollection();
         final E[] elements = getFullElements();
         for (int i = 0; i < elements.length; i++) {
             assertEquals(elements[i], list.get(i), "List should contain correct elements");
             verify();
         }
     }
 
     /**
      *  Tests bounds checking for {@link List#get(int)} on an
      *  empty list.
      */
     @Test
     public void testListGetByIndexBoundsChecking() {
         final List<E> list = makeObject();
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.get(Integer.MIN_VALUE),
                 "List.get should throw IndexOutOfBoundsException [Integer.MIN_VALUE]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.get(-1),
                 "List.get should throw IndexOutOfBoundsException [-1]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.get(0),
                 "List.get should throw IndexOutOfBoundsException [0]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.get(1),
                 "List.get should throw IndexOutOfBoundsException [1]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.get(Integer.MAX_VALUE),
                 "List.get should throw IndexOutOfBoundsException [Integer.MAX_VALUE]");
     }
 
     /**
      *  Tests bounds checking for {@link List#get(int)} on a
      *  full list.
      */
     @Test
     public void testListGetByIndexBoundsChecking2() {
         final List<E> list = makeFullCollection();
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.get(Integer.MIN_VALUE),
                 "List.get should throw IndexOutOfBoundsException [Integer.MIN_VALUE]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.get(-1),
                 "List.get should throw IndexOutOfBoundsException [-1]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.get(getFullElements().length),
                 "List.get should throw IndexOutOfBoundsException [size]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.get(Integer.MAX_VALUE),
                 "List.get should throw IndexOutOfBoundsException [Integer.MAX_VALUE]");
     }
 
     /**
      *  Tests {@link List#hashCode()}.
      */
     @Test
     public void testListHashCode() {
         resetEmpty();
         int hash1 = getCollection().hashCode();
         int hash2 = getConfirmed().hashCode();
         assertEquals(hash1, hash2, "Empty lists should have equal hashCodes");
         verify();
 
         resetFull();
         hash1 = getCollection().hashCode();
         hash2 = getConfirmed().hashCode();
         assertEquals(hash1, hash2, "Full lists should have equal hashCodes");
         verify();
     }
 
     /**
      *  Tests {@link List#indexOf}.
      */
     @Test
     public void testListIndexOf() {
         resetFull();
         final List<E> list1 = getCollection();
         final List<E> list2 = getConfirmed();
 
         for (final E element : list2) {
             assertEquals(list1.indexOf(element),
                     list2.indexOf(element), "indexOf should return correct result");
             verify();
         }
 
         final E[] other = getOtherElements();
         for (final E element : other) {
             assertEquals(-1, list1.indexOf(element),
                     "indexOf should return -1 for nonexistent element");
             verify();
         }
     }
 
     /**
      *  Tests the {@link ListIterator#add(Object)} method of the list
      *  iterator.
      */
     @Test
     public void testListIteratorAdd() {
         if (!isAddSupported()) {
             return;
         }
 
         resetEmpty();
         final List<E> list1 = getCollection();
         final List<E> list2 = getConfirmed();
 
         final E[] elements = getFullElements();
         ListIterator<E> iter1 = list1.listIterator();
         ListIterator<E> iter2 = list2.listIterator();
 
         for (final E element : elements) {
             iter1.add(element);
             iter2.add(element);
             verify();
         }
 
         resetFull();
         iter1 = getCollection().listIterator();
         iter2 = getConfirmed().listIterator();
         for (final E element : elements) {
             iter1.next();
             iter2.next();
             iter1.add(element);
             iter2.add(element);
             verify();
         }
     }
 
     /**
      *  Tests the {@link ListIterator#set(Object)} method of the list
      *  iterator.
      */
     @Test
     public void testListIteratorSet() {
         if (!isSetSupported()) {
             return;
         }
 
         final E[] elements = getFullElements();
 
         resetFull();
         final ListIterator<E> iter1 = getCollection().listIterator();
         final ListIterator<E> iter2 = getConfirmed().listIterator();
         for (final E element : elements) {
             iter1.next();
             iter2.next();
             iter1.set(element);
             iter2.set(element);
             verify();
         }
     }
 
     /**
      *  Tests {@link List#lastIndexOf}.
      */
     @Test
     public void testListLastIndexOf() {
         resetFull();
         final List<E> list1 = getCollection();
         final List<E> list2 = getConfirmed();
 
         for (final E element : list2) {
             assertEquals(list1.lastIndexOf(element), list2.lastIndexOf(element),
                     "lastIndexOf should return correct result");
             verify();
         }
 
         final E[] other = getOtherElements();
         for (final E element : other) {
             assertEquals(-1, list1.lastIndexOf(element),
                     "lastIndexOf should return -1 for nonexistent " + "element");
             verify();
         }
     }
 
     /**
      *  Tests the read-only bits of {@link List#listIterator()}.
      */
     @Test
     public void testListListIterator() {
         resetFull();
         forwardTest(getCollection().listIterator(), 0);
         backwardTest(getCollection().listIterator(), 0);
     }
 
     /**
      *  Tests the read-only bits of {@link List#listIterator(int)}.
      */
     @Test
     public void testListListIteratorByIndex() {
         resetFull();
         assertThrows(IndexOutOfBoundsException.class, () -> getCollection().listIterator(-1));
         resetFull();
         assertThrows(IndexOutOfBoundsException.class, () -> getCollection().listIterator(getCollection().size() + 1));
         resetFull();
         for (int i = 0; i <= getConfirmed().size(); i++) {
             forwardTest(getCollection().listIterator(i), i);
             backwardTest(getCollection().listIterator(i), i);
         }
         resetFull();
         for (int i = 0; i <= getConfirmed().size(); i++) {
             backwardTest(getCollection().listIterator(i), i);
         }
     }
 
     /**
      * Tests remove on list iterator is correct.
      */
     @Test
     public void testListListIteratorNextRemoveNext() {
         if (!isRemoveSupported()) {
             return;
         }
         resetFull();
         if (getCollection().size() < 4) {
             return;
         }
         final ListIterator<E> it = getCollection().listIterator();
         final E zero = it.next();
         final E one = it.next();
         final E two = it.next();
         assertEquals(zero, getCollection().get(0));
         assertEquals(one, getCollection().get(1));
         assertEquals(two, getCollection().get(2));
         final E three = getCollection().get(3);
 
         it.remove(); // removed element at index 2 (two)
         assertEquals(zero, getCollection().get(0));
         assertEquals(one, getCollection().get(1));
         final E three2 = it.next();  // do next after remove
         assertEquals(three, three2);
         assertEquals(getCollection().size() > 3, it.hasNext());
         assertTrue(it.hasPrevious());
     }
 
     /**
      * Tests remove on list iterator is correct.
      */
     @Test
     public void testListListIteratorNextRemovePrevious() {
         if (!isRemoveSupported()) {
             return;
         }
         resetFull();
         if (getCollection().size() < 4) {
             return;
         }
         final ListIterator<E> it = getCollection().listIterator();
         final E zero = it.next();
         final E one = it.next();
         final E two = it.next();
         assertEquals(zero, getCollection().get(0));
         assertEquals(one, getCollection().get(1));
         assertEquals(two, getCollection().get(2));
 
         it.remove(); // removed element at index 2 (two)
         assertEquals(zero, getCollection().get(0));
         assertEquals(one, getCollection().get(1));
         final E one2 = it.previous();  // do previous after remove
         assertEquals(one, one2);
         assertTrue(it.hasNext());
         assertTrue(it.hasPrevious());
     }
 
     /**
      * Tests remove on list iterator is correct.
      */
     @Test
     public void testListListIteratorPreviousRemoveNext() {
         if (!isRemoveSupported()) {
             return;
         }
         resetFull();
         if (getCollection().size() < 4) {
             return;
         }
         final ListIterator<E> it = getCollection().listIterator();
         final E zero = it.next();
         final E one = it.next();
         final E two = it.next();
         final E two2 = it.previous();
         final E one2 = it.previous();
         assertEquals(one, one2);
         assertEquals(two, two2);
         assertEquals(zero, getCollection().get(0));
         assertEquals(one, getCollection().get(1));
         assertEquals(two, getCollection().get(2));
 
         it.remove(); // removed element at index 1 (one)
         assertEquals(zero, getCollection().get(0));
         assertEquals(two, getCollection().get(1));
         final E two3 = it.next();  // do next after remove
         assertEquals(two, two3);
         assertEquals(getCollection().size() > 2, it.hasNext());
         assertTrue(it.hasPrevious());
     }
 
     /**
      * Tests remove on list iterator is correct.
      */
     @Test
     public void testListListIteratorPreviousRemovePrevious() {
         if (!isRemoveSupported()) {
             return;
         }
         resetFull();
         if (getCollection().size() < 4) {
             return;
         }
         final ListIterator<E> it = getCollection().listIterator();
         final E zero = it.next();
         final E one = it.next();
         final E two = it.next();
         final E two2 = it.previous();
         final E one2 = it.previous();
         assertEquals(one, one2);
         assertEquals(two, two2);
         assertEquals(zero, getCollection().get(0));
         assertEquals(one, getCollection().get(1));
         assertEquals(two, getCollection().get(2));
 
         it.remove(); // removed element at index 1 (one)
         assertEquals(zero, getCollection().get(0));
         assertEquals(two, getCollection().get(1));
         final E zero3 = it.previous();  // do previous after remove
         assertEquals(zero, zero3);
         assertFalse(it.hasPrevious());
         assertEquals(getCollection().size() > 2, it.hasNext());
     }
 
     /**
      *  Tests {@link List#remove(int)}.
      */
     @Test
     public void testListRemoveByIndex() {
         if (!isRemoveSupported()) {
             return;
         }
 
         final int max = getFullElements().length;
         for (int i = 0; i < max; i++) {
             resetFull();
             final E o1 = getCollection().remove(i);
             final E o2 = getConfirmed().remove(i);
             assertEquals(o1, o2, "remove should return correct element");
             verify();
         }
     }
 
     /**
      *  Tests bounds checking for {@link List#remove(int)} on an
      *  empty list.
      */
     @Test
     public void testListRemoveByIndexBoundsChecking() {
         if (!isRemoveSupported()) {
             return;
         }
 
         final List<E> list = makeObject();
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.remove(Integer.MIN_VALUE),
                 "List.remove should throw IndexOutOfBoundsException [Integer.MIN_VALUE]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.remove(-1),
                 "List.remove should throw IndexOutOfBoundsException [-1]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.remove(0),
                 "List.remove should throw IndexOutOfBoundsException [0]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.remove(1),
                 "List.remove should throw IndexOutOfBoundsException [1]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.remove(Integer.MAX_VALUE),
                 "List.remove should throw IndexOutOfBoundsException [Integer.MAX_VALUE]");
     }
 
     /**
      *  Tests bounds checking for {@link List#remove(int)} on a
      *  full list.
      */
     @Test
     public void testListRemoveByIndexBoundsChecking2() {
         if (!isRemoveSupported()) {
             return;
         }
 
         final List<E> list = makeFullCollection();
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.remove(Integer.MIN_VALUE),
                 "List.remove should throw IndexOutOfBoundsException [Integer.MIN_VALUE]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.remove(-1),
                 "List.remove should throw IndexOutOfBoundsException [-1]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.remove(getFullElements().length),
                 "List.remove should throw IndexOutOfBoundsException [size]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.remove(Integer.MAX_VALUE),
                 "List.remove should throw IndexOutOfBoundsException [Integer.MAX_VALUE]");
     }
 
     /**
      *  Test {@link List#set(int,Object)}.
      */
     @Test
     public void testListSetByIndex() {
         if (!isSetSupported()) {
             return;
         }
 
         resetFull();
         final E[] elements = getFullElements();
         final E[] other = getOtherElements();
 
         for (int i = 0; i < elements.length; i++) {
             final E n = other[i % other.length];
             final E v = getCollection().set(i, n);
             assertEquals(elements[i], v, "Set should return correct element");
             getConfirmed().set(i, n);
             verify();
         }
     }
 
     /**
      *  Tests bounds checking for {@link List#set(int,Object)} on an
      *  empty list.
      */
     @Test
     public void testListSetByIndexBoundsChecking() {
         if (!isSetSupported()) {
             return;
         }
 
         final List<E> list = makeObject();
         final E element = getOtherElements()[0];
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.set(Integer.MIN_VALUE, element),
                 "List.set should throw IndexOutOfBoundsException [Integer.MIN_VALUE]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.set(-1, element),
                 "List.set should throw IndexOutOfBoundsException [-1]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.set(0, element),
                 "List.set should throw IndexOutOfBoundsException [0]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.set(1, element),
                 "List.set should throw IndexOutOfBoundsException [1]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.set(Integer.MAX_VALUE, element),
                 "List.set should throw IndexOutOfBoundsException [Integer.MAX_VALUE]");
     }
 
     /**
      *  Tests bounds checking for {@link List#set(int,Object)} on a
      *  full list.
      */
     @Test
     public void testListSetByIndexBoundsChecking2() {
         if (!isSetSupported()) {
             return;
         }
 
         final List<E> list = makeFullCollection();
         final E element = getOtherElements()[0];
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.set(Integer.MIN_VALUE, element),
                 "List.set should throw IndexOutOfBoundsException [Integer.MIN_VALUE]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.set(-1, element),
                 "List.set should throw IndexOutOfBoundsException [-1]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.set(getFullElements().length, element),
                 "List.set should throw IndexOutOfBoundsException [size]");
 
         assertThrows(IndexOutOfBoundsException.class, () -> list.set(Integer.MAX_VALUE, element),
                 "List.set should throw IndexOutOfBoundsException [Integer.MAX_VALUE]");
     }
 
     /**
      * Tests that a sublist raises a {@link java.util.ConcurrentModificationException ConcurrentModificationException}
      * if elements are added to the original list.
      */
     @Test
     public void testListSubListFailFastOnAdd() {
         if (!isFailFastSupported()) {
             return;
         }
         if (!isAddSupported()) {
             return;
         }
 
         resetFull();
         final int size = getCollection().size();
         List<E> sub = getCollection().subList(1, size);
         getCollection().add(getOtherElements()[0]);
         failFastAll(sub);
 
         resetFull();
         sub = getCollection().subList(1, size);
         getCollection().add(0, getOtherElements()[0]);
         failFastAll(sub);
 
         resetFull();
         sub = getCollection().subList(1, size);
         getCollection().addAll(Arrays.asList(getOtherElements()));
         failFastAll(sub);
 
         resetFull();
         sub = getCollection().subList(1, size);
         getCollection().addAll(0, Arrays.asList(getOtherElements()));
         failFastAll(sub);
     }
 
     /**
      * Tests that a sublist raises a {@link java.util.ConcurrentModificationException ConcurrentModificationException}
      * if elements are removed from the original list.
      */
     @Test
     public void testListSubListFailFastOnRemove() {
         if (!isFailFastSupported()) {
             return;
         }
         if (!isRemoveSupported()) {
             return;
         }
 
         resetFull();
         final int size = getCollection().size();
         List<E> sub = getCollection().subList(1, size);
         getCollection().remove(0);
         failFastAll(sub);
 
         resetFull();
         sub = getCollection().subList(1, size);
         getCollection().remove(getFullElements()[2]);
         failFastAll(sub);
 
         resetFull();
         sub = getCollection().subList(1, size);
         getCollection().removeAll(Arrays.asList(getFullElements()));
         failFastAll(sub);
 
         resetFull();
         sub = getCollection().subList(1, size);
         getCollection().retainAll(Arrays.asList(getOtherElements()));
         failFastAll(sub);
 
         resetFull();
         sub = getCollection().subList(1, size);
         getCollection().clear();
         failFastAll(sub);
     }
 
     /**
      *  If {@link #isSetSupported()} returns false, tests that set operation
      *  raises <Code>UnsupportedOperationException.
      */
     @Test
     public void testUnsupportedSet() {
         if (isSetSupported()) {
             return;
         }
 
         resetFull();
         assertThrows(UnsupportedOperationException.class, () -> getCollection().set(0, getFullElements()[0]),
                 "Empty collection should not support set.");
         // make sure things didn't change even if the expected exception was
         // thrown.
         verify();
     }
 
     /**
      *  Verifies that the test list implementation matches the confirmed list
      *  implementation.
      */
     @Override
     @SuppressWarnings("unchecked")
     public void verify() {
         super.verify();
 
         final List<E> list1 = getCollection();
         final List<E> list2 = getConfirmed();
 
         assertEquals(list1, list2, "List should equal confirmed");
         assertEquals(list2, list1, "Confirmed should equal list");
 
         assertEquals(list1.hashCode(), list2.hashCode(), "Hash codes should be equal");
 
         int i = 0;
         final Iterator<E> iterator1 = list1.iterator();
         final E[] array = (E[]) list1.toArray();
         for (Object o2 : list2) {
             assertTrue(iterator1.hasNext(), "List iterator should have next");
             final Object o1 = iterator1.next();
             assertEquals(o1, o2, "Iterator elements should be equal");
             o2 = list1.get(i);
             assertEquals(o1, o2, "get should return correct element");
             o2 = array[i];
             assertEquals(o1, o2, "toArray should have correct element");
             i++;
         }
     }
 
 }