@Override
        public @Nullable Object execute(Iterator<?> iterator) {
          iterator.remove();
          return null;
        }
      };

  private static final IteratorOperation NEXT_METHOD =
      new IteratorOperation() {
        @Override
        public @Nullable Object execute(Iterator<?> iterator) {
          return iterator.next();
        }
      };

  public void testCopyOf_iterator_empty() {
    Iterator<String> iterator = emptyIterator();
    Set<String> set = copyOf(iterator);
    assertEquals(Collections.<String>emptySet(), set);
    assertSame(this.<String>of(), set);
  }

  public void testCopyOf_iterator_oneElement() {
    Iterator<String> iterator = singletonIterator("a");
    Set<String> set = copyOf(iterator);
    assertEquals(singleton("a"), set);
  }

    Iterator<String> iterator = skip(list, 2).iterator();
    assertThrows(IllegalStateException.class, () -> iterator.remove());
  }

  public void testSkip_allOfImmutableList_modifiable() {
    List<String> list = ImmutableList.of("a", "b");
    Iterator<String> iterator = skip(list, 2).iterator();
    assertThrows(UnsupportedOperationException.class, () -> iterator.remove());
  }

  /**
   * A sensible definition of {@link #firstEntry()} in terms of {@code entrySet().iterator()}.
   *
   * <p>If you override {@link #entrySet()}, you may wish to override {@link #firstEntry()} to
   * forward to this implementation.
   */
  protected @Nullable Entry<E> standardFirstEntry() {
    Iterator<Entry<E>> entryIterator = entrySet().iterator();
    if (!entryIterator.hasNext()) {
      return null;
    }

        return parent.indexOf(o);
    }

    @Override
    public boolean isEmpty() {
        return parent.isEmpty();
    }

    @Override
    public Iterator<Map<String, Object>> iterator() {
        return parent.iterator();
    }

    @Override
    public int lastIndexOf(final Object o) {
        return parent.lastIndexOf(o);
    }

    @Override

  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)
  public void testIteratorRemove_unsupported() {
    Iterator<E> iterator = collection.iterator();
    iterator.next();
    assertThrows(UnsupportedOperationException.class, iterator::remove);
    expectUnchanged();
    assertTrue(collection.contains(e0()));
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)

      @Override
      protected Iterator<E> newTargetIterator() {
        resetCollection();
        return collection.iterator();
      }

      @Override
      protected void verify(List<E> elements) {
        expectContents(elements);
      }
    }.test();
  }

  public void testIteratorNoSuchElementException() {
    Iterator<E> iterator = collection.iterator();
    while (iterator.hasNext()) {

  private ClusterException(Collection<? extends Throwable> exceptions) {
    super(
        exceptions.size() + " exceptions were thrown. The first exception is listed as a cause.",
        exceptions.iterator().next());
    ArrayList<? extends Throwable> temp = new ArrayList<>(exceptions);
    this.exceptions = Collections.unmodifiableCollection(temp);
  }

  /** See {@link #create(Collection)}. */

    assertFalse(getMap().entrySet().iterator().hasNext());
  }

  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
  @CollectionSize.Require(SEVERAL)
  public void testClearConcurrentWithEntrySetIteration() {
    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<Entry<K, V>> iterator = getMap().entrySet().iterator();
          getMap().clear();

    assertThrows(NoSuchElementException.class, () -> iterator.next());
    assertThrows(IllegalStateException.class, () -> iterable.iterator());
  }

  public void testOf_one() {
    Iterable<String> iterable = MinimalIterable.of("a");
    Iterator<String> iterator = iterable.iterator();
    assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    assertFalse(iterator.hasNext());