}
  }

  /** If this collection is backed by an array of its elements in insertion order, returns it. */
  Object @Nullable [] internalArray() {
    return null;
  }

  /**
   * If this collection is backed by an array of its elements in insertion order, returns the offset
   * where this collection's elements start.
   */
  int internalArrayStart() {

  }

  // Following Javadoc copied from ListMultimap.

  /**
   * {@inheritDoc}
   *
   * <p>Because the values for a given key may have duplicates and follow the insertion ordering,
   * this method returns a {@link List}, instead of the {@link Collection} specified in the {@link
   * Multimap} interface.
   */
  @Override
  public List<V> get(@ParametricNullness K key) {

   *         <li>{@code edges()}: Stable order
   *         <li>{@code adjacentNodes(node)}: Connecting edge insertion order
   *         <li>{@code predecessors(node)}: Connecting edge insertion order
   *         <li>{@code successors(node)}: Connecting edge insertion order
   *         <li>{@code incidentEdges(node)}: Edge insertion order
   *       </ul>
   *   <li>For {@link Network}:
   *       <ul>

    return Arrays.asList(
        new Object[][] {
          {false, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {true, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {false, false, naturalElementOrder, naturalElementOrder},
          {true, true, ElementOrder.insertion(), ElementOrder.insertion()},
        });
  }

  private final boolean allowsSelfLoops;

  @Test
  public void nodeOrder_insertion() {
    MutableGraph<Integer> graph = GraphBuilder.directed().nodeOrder(insertion()).build();

    addNodes(graph);

    assertThat(graph.nodeOrder()).isEqualTo(insertion());
    assertThat(graph.nodes()).containsExactly(3, 1, 4).inOrder();
  }

  // The default ordering is INSERTION unless otherwise specified.
  @Test
  public void nodeOrder_default() {

    return Arrays.asList(
        new Object[][] {
          {false, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {true, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {false, false, naturalElementOrder, naturalElementOrder},
          {true, true, ElementOrder.insertion(), ElementOrder.insertion()},
        });
  }

  private final boolean allowsSelfLoops;

    return Arrays.asList(
        new Object[][] {
          {false, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {true, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {false, false, naturalElementOrder, naturalElementOrder},
          {true, true, ElementOrder.insertion(), ElementOrder.insertion()},
        });
  }

  private final boolean allowsSelfLoops;

    return Arrays.asList(
        new Object[][] {
          {false, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {true, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {false, false, naturalElementOrder, naturalElementOrder},
          {true, true, ElementOrder.insertion(), ElementOrder.insertion()},
        });
  }

  private final boolean allowsSelfLoops;

    return Arrays.asList(
        new Object[][] {
          {false, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {true, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {false, false, naturalElementOrder, naturalElementOrder},
          {true, true, ElementOrder.insertion(), ElementOrder.insertion()},
        });
  }

  private final boolean allowsSelfLoops;

    return Arrays.asList(
        new Object[][] {
          {false, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {true, false, ElementOrder.insertion(), ElementOrder.insertion()},
          {false, false, naturalElementOrder, naturalElementOrder},
          {true, true, ElementOrder.insertion(), ElementOrder.insertion()},
        });
  }

  private final boolean allowsSelfLoops;