assertEquals(
        "next() should still return first element after peeking", "A", peekingIterator.next());

    assertEquals("Should be able to peek() at middle element", "B", peekingIterator.peek());
    assertEquals(
        "Should be able to peek() middle element multiple times", "B", peekingIterator.peek());
    assertEquals(

         * @param value
         *            the value
         * @param next
         *            the next entry
         */
        public Entry(final int hashCode, final K key, final V value, final Entry<K, V> next) {
            this.hashCode = hashCode;
            this.key = key;
            this.value = value;
            this.next = next;
        }

        @Override
        public K getKey() {

    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());

      @Override
      @ParametricNullness
      public T next() {
        T next = iterator.next();
        iterator.remove();
        return next;
      }

      @Override
      public String toString() {
        return "Iterators.consumingIterator(...)";
      }
    };
  }

  /**
   * Deletes and returns the next value from the iterator, or returns {@code null} if there is no

      @Override
      @ParametricNullness
      public T next() {
        T next = iterator.next();
        iterator.remove();
        return next;
      }

      @Override
      public String toString() {
        return "Iterators.consumingIterator(...)";
      }
    };
  }

  /**
   * Deletes and returns the next value from the iterator, or returns {@code null} if there is no

      final Runnable runnable;
      final Executor executor;
      @Nullable final RunnableExecutorPair next;

      RunnableExecutorPair(Runnable runnable, Executor executor, RunnableExecutorPair next) {
        this.runnable = runnable;
        this.executor = executor;
        this.next = next;
      }
    }
  }

       * initialized by next() -- which initializes rowEntry, too.
       *
       * - rowEntry isn't cleared except below. If it was cleared below, then either
       *   columnIterator.remove() would have failed above (if the user hasn't called next() since
       *   then) or rowEntry would have been initialized by next() (as discussed above).
       */

    assertEquals((Integer) 12, it.next());
    assertEquals((Integer) 30, it.next());
    assertEquals((Integer) 40, it.next());
    // Skipping 20
    assertEquals((Integer) 11, it.next());
    // Not skipping 400, because it moved back down
    assertEquals((Integer) 400, it.next());
    assertEquals((Integer) 13, it.next());
    assertEquals((Integer) 200, it.next());
    assertEquals((Integer) 300, it.next());

        this.existPrePage = existPrePage;
    }

    /**
     * Checks if a next page exists.
     * @return true if a next page exists, false otherwise.
     */
    public boolean isExistNextPage() {
        return existNextPage;
    }

    /**
     * Sets whether a next page exists.
     * @param existNextPage true if a next page exists, false otherwise.
     */

    }

    /**
     * Checks if there is a next page available.
     *
     * @return true if next page exists, false otherwise
     */
    public boolean isExistNextPage() {
        return existNextPage;
    }

    /**
     * Sets whether there is a next page available.
     *
     * @param existNextPage true if next page exists, false otherwise
     */