Merge pull request #3663 from nguyennamthai/BAEL-1537
Initial commit for List TDD
This commit is contained in:
Tom Hombergs
GitHub
commit
62c1a46b01
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package com.baeldung.java.list;
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import java.util.Arrays;
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import java.util.Collection;
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import java.util.Iterator;
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import java.util.List;
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import java.util.ListIterator;
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public class CustomList<E> implements List<E> {
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private Object[] internal = {};
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@Override
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public void add(int index, E element) {
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throw new UnsupportedOperationException();
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}
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@Override
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public boolean addAll(Collection<? extends E> collection) {
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throw new UnsupportedOperationException();
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}
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@Override
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public boolean addAll(int index, Collection<? extends E> collection) {
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throw new UnsupportedOperationException();
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}
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@Override
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public E remove(int index) {
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throw new UnsupportedOperationException();
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}
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@Override
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public boolean remove(Object object) {
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throw new UnsupportedOperationException();
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}
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@Override
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public boolean removeAll(Collection<?> collection) {
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throw new UnsupportedOperationException();
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}
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@Override
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public boolean retainAll(Collection<?> collection) {
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throw new UnsupportedOperationException();
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}
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@Override
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public int size() {
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return internal.length;
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}
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@Override
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public boolean isEmpty() {
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return internal.length == 0;
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}
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@Override
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public boolean add(E element) {
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// the first cycle
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// internal = new Object[1];
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// internal[0] = element;
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// return true;
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Object[] temp = new Object[internal.length + 1];
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System.arraycopy(internal, 0, temp, 0, internal.length);
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temp[internal.length] = element;
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internal = temp;
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return true;
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}
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@SuppressWarnings("unchecked")
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@Override
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public E get(int index) {
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return (E) internal[index];
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}
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@Override
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public boolean contains(Object object) {
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// return false
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for (Object element : internal) {
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if (object.equals(element)) {
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return true;
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}
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}
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return false;
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}
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@Override
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public boolean containsAll(Collection<?> collection) {
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// the first cycle
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// for (Object element : collection) {
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// if (element.equals(internal[0])) {
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// return true;
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// }
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// }
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// return false;
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for (Object element : collection)
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if (!contains(element)) {
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return false;
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}
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return true;
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}
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@SuppressWarnings("unchecked")
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@Override
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public E set(int index, E element) {
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E oldElement = (E) internal[index];
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internal[index] = element;
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return oldElement;
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}
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@Override
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public void clear() {
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internal = new Object[0];
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}
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@Override
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public int indexOf(Object object) {
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// the first cycle
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// if (object.equals(internal[0])) {
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// return 0;
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// }
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// return -1;
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for (int i = 0; i < internal.length; i++) {
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if (object.equals(internal[i])) {
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return i;
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}
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}
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return -1;
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}
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@Override
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public int lastIndexOf(Object object) {
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// the first cycle
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// if (object.equals(internal[0])) {
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// return 0;
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// }
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// return -1;
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for (int i = internal.length - 1; i >= 0; i--) {
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if (object.equals(internal[i])) {
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return i;
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}
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}
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return -1;
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}
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@SuppressWarnings("unchecked")
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@Override
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public List<E> subList(int fromIndex, int toIndex) {
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// the first cycle
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// return (List<E>) Arrays.asList(internal);
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Object[] temp = new Object[toIndex - fromIndex];
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System.arraycopy(internal, fromIndex, temp, 0, temp.length);
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return (List<E>) Arrays.asList(temp);
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}
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@Override
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public Object[] toArray() {
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return Arrays.copyOf(internal, internal.length);
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}
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@SuppressWarnings("unchecked")
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@Override
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public <T> T[] toArray(T[] array) {
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// the first cycle
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// array[0] = (T) internal[0];
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// return array;
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// the second cycle
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// if (array.length < internal.length) {
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// return (T[]) Arrays.copyOf(internal, internal.length, array.getClass());
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// }
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// return (T[]) Arrays.copyOf(internal, internal.length, array.getClass());
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if (array.length < internal.length) {
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return (T[]) Arrays.copyOf(internal, internal.length, array.getClass());
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}
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System.arraycopy(internal, 0, array, 0, internal.length);
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if (array.length > internal.length) {
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array[internal.length] = null;
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}
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return array;
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}
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@Override
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public Iterator<E> iterator() {
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return new CustomIterator();
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}
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@Override
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public ListIterator<E> listIterator() {
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return null;
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}
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@Override
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public ListIterator<E> listIterator(int index) {
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// ignored for brevity
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return null;
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}
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private class CustomIterator implements Iterator<E> {
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int index;
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@Override
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public boolean hasNext() {
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// the first cycle
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// return true;
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return index != internal.length;
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}
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@SuppressWarnings("unchecked")
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@Override
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public E next() {
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// the first cycle
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// return (E) CustomList.this.internal[0];
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E element = (E) CustomList.this.internal[index];
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index++;
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return element;
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}
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}
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}
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@ -0,0 +1,282 @@
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package com.baeldung.java.list;
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import static org.junit.Assert.assertArrayEquals;
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import static org.junit.Assert.assertEquals;
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import static org.junit.Assert.assertFalse;
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import static org.junit.Assert.assertNull;
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import static org.junit.Assert.assertTrue;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.Iterator;
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import java.util.List;
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import org.junit.Test;
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public class CustomListUnitTest {
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@Test(expected = UnsupportedOperationException.class)
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public void whenAddToSpecifiedIndex_thenExceptionIsThrown() {
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new CustomList<>().add(0, null);
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}
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@Test(expected = UnsupportedOperationException.class)
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public void whenAddAllToTheEnd_thenExceptionIsThrown() {
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Collection<Object> collection = new ArrayList<>();
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List<Object> list = new CustomList<>();
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list.addAll(collection);
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}
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@Test(expected = UnsupportedOperationException.class)
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public void whenAddAllToSpecifiedIndex_thenExceptionIsThrown() {
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Collection<Object> collection = new ArrayList<>();
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List<Object> list = new CustomList<>();
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list.addAll(0, collection);
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}
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@Test(expected = UnsupportedOperationException.class)
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public void whenRemoveAtSpecifiedIndex_thenExceptionIsThrown() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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list.remove(0);
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}
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@Test(expected = UnsupportedOperationException.class)
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public void whenRemoveSpecifiedElement_thenExceptionIsThrown() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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list.remove("baeldung");
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}
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@Test(expected = UnsupportedOperationException.class)
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public void whenRemoveAll_thenExceptionIsThrown() {
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Collection<Object> collection = new ArrayList<>();
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collection.add("baeldung");
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List<Object> list = new CustomList<>();
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list.removeAll(collection);
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}
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@Test(expected = UnsupportedOperationException.class)
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public void whenRetainAll_thenExceptionIsThrown() {
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Collection<Object> collection = new ArrayList<>();
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collection.add("baeldung");
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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list.retainAll(collection);
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}
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@Test
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public void givenEmptyList_whenSize_thenZeroIsReturned() {
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List<Object> list = new CustomList<>();
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assertEquals(0, list.size());
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}
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@Test
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public void givenEmptyList_whenIsEmpty_thenTrueIsReturned() {
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List<Object> list = new CustomList<>();
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assertTrue(list.isEmpty());
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}
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@Test
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public void givenEmptyList_whenElementIsAdded_thenGetReturnsThatElement() {
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List<Object> list = new CustomList<>();
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boolean succeeded = list.add("baeldung");
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Object element = list.get(0);
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assertTrue(succeeded);
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assertEquals("baeldung", element);
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}
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@Test
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public void givenListWithAnElement_whenAnotherIsAdded_thenGetReturnsBoth() {
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List<Object> list = new CustomList<>();
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boolean succeeded1 = list.add("baeldung");
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boolean succeeded2 = list.add(".com");
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Object element1 = list.get(0);
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Object element2 = list.get(1);
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assertTrue(succeeded1);
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assertTrue(succeeded2);
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assertEquals("baeldung", element1);
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assertEquals(".com", element2);
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}
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@Test
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public void givenEmptyList_whenContains_thenFalseIsReturned() {
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List<Object> list = new CustomList<>();
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assertFalse(list.contains(null));
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}
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@Test
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public void givenListWithAnElement_whenContains_thenTrueIsReturned() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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assertTrue(list.contains("baeldung"));
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}
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@Test
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public void givenListWithAnElement_whenContainsAll_thenTrueIsReturned() {
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Collection<Object> collection = new ArrayList<>();
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collection.add("baeldung");
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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assertTrue(list.containsAll(collection));
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}
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@Test
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public void givenList_whenContainsAll_thenEitherTrueOrFalseIsReturned() {
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Collection<Object> collection1 = new ArrayList<>();
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collection1.add("baeldung");
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collection1.add(".com");
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Collection<Object> collection2 = new ArrayList<>();
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collection2.add("baeldung");
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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assertFalse(list.containsAll(collection1));
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assertTrue(list.containsAll(collection2));
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}
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@Test
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public void givenList_whenSet_thenOldElementIsReturned() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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Object element = list.set(0, null);
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assertEquals("baeldung", element);
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assertNull(list.get(0));
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}
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@Test
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public void givenList_whenClear_thenAllElementsAreRemoved() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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list.clear();
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assertTrue(list.isEmpty());
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}
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@Test
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public void givenList_whenIndexOf_thenIndexZeroIsReturned() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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assertEquals(0, list.indexOf("baeldung"));
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}
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@Test
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public void givenList_whenIndexOf_thenPositiveIndexOrMinusOneIsReturned() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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list.add(".com");
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list.add(".com");
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assertEquals(1, list.indexOf(".com"));
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assertEquals(-1, list.indexOf("com"));
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}
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@Test
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public void whenLastIndexOf_thenIndexZeroIsReturned() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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assertEquals(0, list.lastIndexOf("baeldung"));
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}
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@Test
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public void whenLastIndexOf_thenPositiveIndexOrMinusOneIsReturned() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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list.add("baeldung");
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list.add(".com");
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assertEquals(1, list.lastIndexOf("baeldung"));
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assertEquals(-1, list.indexOf("com"));
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}
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@Test
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public void whenSubListZeroToOne_thenListContainingFirstElementIsReturned() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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List<Object> subList = list.subList(0, 1);
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assertEquals("baeldung", subList.get(0));
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}
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@Test
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public void whenSubListOneToTwo_thenListContainingSecondElementIsReturned() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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list.add(".");
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list.add("com");
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List<Object> subList = list.subList(1, 2);
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assertEquals(1, subList.size());
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assertEquals(".", subList.get(0));
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}
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@Test
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public void givenListWithElements_whenToArray_thenArrayContainsThose() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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list.add(".com");
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Object[] array = list.toArray();
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assertArrayEquals(new Object[] { "baeldung", ".com" }, array);
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}
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@Test
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public void givenListWithAnElement_whenToArray_thenInputArrayIsReturned() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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String[] input = new String[1];
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String[] output = list.toArray(input);
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assertArrayEquals(new String[] { "baeldung" }, input);
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}
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@Test
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public void whenToArrayIsCalledWithEmptyInputArray_thenNewArrayIsReturned() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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String[] input = {};
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String[] output = list.toArray(input);
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assertArrayEquals(new String[] { "baeldung" }, output);
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}
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@Test
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public void whenToArrayIsCalledWithLargerInput_thenOutputHasTrailingNull() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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String[] input = new String[2];
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String[] output = list.toArray(input);
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assertArrayEquals(new String[] { "baeldung", null }, output);
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}
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@Test
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public void givenListWithOneElement_whenIterator_thenThisElementIsNext() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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Iterator<Object> iterator = list.iterator();
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assertTrue(iterator.hasNext());
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assertEquals("baeldung", iterator.next());
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}
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@Test
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public void whenIteratorNextIsCalledTwice_thenTheSecondReturnsFalse() {
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List<Object> list = new CustomList<>();
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list.add("baeldung");
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Iterator<Object> iterator = list.iterator();
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iterator.next();
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assertFalse(iterator.hasNext());
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}
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}
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