public void testSet_replacingNull() {
    E[] elements = createSamplesArray();
    int i = aValidIndex();
    elements[i] = null;
    collection = getSubjectGenerator().create(elements);

    doTestSet(e3());
  }

  private void doTestSet(E newValue) {
    int index = aValidIndex();
    E initialValue = getList().get(index);
    assertEquals(
        "set(i, x) should return the old element at position i.",
        initialValue,

   * IllegalArgumentException}.
   */
  @Override
  boolean allowsSelfLoops();

  /** Returns the order of iteration for the elements of {@link #nodes()}. */
  @Override
  ElementOrder<N> nodeOrder();

  /**
   * Returns an {@link ElementOrder} that specifies the order of iteration for the elements of
   * {@link #edges()}, {@link #adjacentNodes(Object)}, {@link #predecessors(Object)}, {@link

   * IllegalArgumentException}.
   */
  @Override
  boolean allowsSelfLoops();

  /** Returns the order of iteration for the elements of {@link #nodes()}. */
  @Override
  ElementOrder<N> nodeOrder();

  /**
   * Returns an {@link ElementOrder} that specifies the order of iteration for the elements of
   * {@link #edges()}, {@link #adjacentNodes(Object)}, {@link #predecessors(Object)}, {@link

	</li>
	<li>An element list that does not contain any keys must
	    list an element for each struct field in the
	    order in which the fields are declared.
	</li>
	<li>If any element has a key, every element must have a key.
	</li>
	<li>An element list that contains keys does not need to
	    have an element for each struct field. Omitted fields

      long tmp = array[i];
      array[i] = array[j];
      array[j] = tmp;
    }
  }

  /**
   * Performs a right rotation of {@code array} of "distance" places, so that the first element is
   * moved to index "distance", and the element at index {@code i} ends up at index {@code (distance
   * + i) mod array.length}. This is equivalent to {@code Collections.rotate(Longs.asList(array),

      long tmp = array[i];
      array[i] = array[j];
      array[j] = tmp;
    }
  }

  /**
   * Performs a right rotation of {@code array} of "distance" places, so that the first element is
   * moved to index "distance", and the element at index {@code i} ends up at index {@code (distance
   * + i) mod array.length}. This is equivalent to {@code Collections.rotate(Longs.asList(array),

   * IllegalArgumentException}.
   */
  boolean allowsSelfLoops();

  /** Returns the order of iteration for the elements of {@link #nodes()}. */
  ElementOrder<N> nodeOrder();

  /** Returns the order of iteration for the elements of {@link #edges()}. */
  ElementOrder<E> edgeOrder();

  //
  // Element-level accessors
  //

  /**

            listener.warning(String.format("Unsupported HTML element <%s>", elementName));
            Element element = document.createElement("UNHANDLED-ELEMENT");
            element.appendChild(document.createTextNode(String.format("<%s>", elementName)));
            nodes.push(element);
            return true;
        }

        @Override
        public void onText(String text) {

		},
		// With a list of only one element nothing to sort.
		{
			ipList:       []string{"hostname"},
			sortedIPList: []string{"hostname"},
		},
		// With a list of only one element nothing to sort.
		{
			ipList:       []string{"127.0.0.1"},
			sortedIPList: []string{"127.0.0.1"},
		},
		// Non parsable ip is assumed to be hostame and gets preserved
		// as the left most elements, regardless of IP based sorting.
		{

   *       href="https://github.com/google/guava/wiki/GraphsExplained#graph-elements-nodes-and-edges">
   *       graph elements</a> for details)
   * </ul>
   *
   * @throws IllegalArgumentException if {@code node} is not an element of this graph
   */
  Iterable<? extends N> predecessors(N node);