* @throws IllegalArgumentException if {@code incidentEdgeOrder} is not either {@code
   *     ElementOrder.unordered()} or {@code ElementOrder.stable()}.
   * @since 29.0
   */
  public <N1 extends N> ValueGraphBuilder<N1, V> incidentEdgeOrder(
      ElementOrder<N1> incidentEdgeOrder) {
    checkArgument(
        incidentEdgeOrder.type() == ElementOrder.Type.UNORDERED
            || incidentEdgeOrder.type() == ElementOrder.Type.STABLE,

        });
  }

  private final boolean allowsSelfLoops;
  private final ElementOrder<Integer> incidentEdgeOrder;

  public StandardMutableUndirectedGraphTest(
      boolean allowsSelfLoops, ElementOrder<Integer> incidentEdgeOrder) {
    this.allowsSelfLoops = allowsSelfLoops;
    this.incidentEdgeOrder = incidentEdgeOrder;
  }

  @Override
  public MutableGraph<Integer> createGraph() {
    return GraphBuilder.undirected()

    assertThat(immutableValueGraph.incidentEdgeOrder()).isEqualTo(ElementOrder.stable());
  }

  @Test
  public void incidentEdgeOrder_fromUnorderedGraph_stable() {
    ImmutableValueGraph<String, Integer> immutableValueGraph =
        ImmutableValueGraph.copyOf(
            ValueGraphBuilder.directed()
                .incidentEdgeOrder(ElementOrder.unordered())
                .<String, Integer>build());

    assume().that(graph.incidentEdgeOrder().type()).isEqualTo(ElementOrder.Type.STABLE);

    populateTShapedGraph();

    assertThat(graph.adjacentNodes(1)).containsExactly(2, 4, 3).inOrder();
  }

  @Test
  public void stableIncidentEdgeOrder_predecessors_returnsInConnectingEdgeInsertionOrder() {
    assume().that(graph.incidentEdgeOrder().type()).isEqualTo(ElementOrder.Type.STABLE);

        });
  }

  private final boolean allowsSelfLoops;
  private final ElementOrder<Integer> incidentEdgeOrder;

  public StandardMutableUndirectedGraphTest(
      boolean allowsSelfLoops, ElementOrder<Integer> incidentEdgeOrder) {
    this.allowsSelfLoops = allowsSelfLoops;
    this.incidentEdgeOrder = incidentEdgeOrder;
  }

  @Override
  public MutableGraph<Integer> createGraph() {
    return GraphBuilder.undirected()

    return delegate().allowsSelfLoops();
  }

  @Override
  public ElementOrder<N> nodeOrder() {
    return delegate().nodeOrder();
  }

  @Override
  public ElementOrder<N> incidentEdgeOrder() {
    return delegate().incidentEdgeOrder();
  }

  @Override
  public Set<N> adjacentNodes(N node) {
    return delegate().adjacentNodes(node);
  }

  @Override
  public Set<N> predecessors(N node) {

        });
  }

  private final boolean allowsSelfLoops;
  private final ElementOrder<Integer> incidentEdgeOrder;

  public StandardMutableDirectedGraphTest(
      boolean allowsSelfLoops, ElementOrder<Integer> incidentEdgeOrder) {
    this.allowsSelfLoops = allowsSelfLoops;
    this.incidentEdgeOrder = incidentEdgeOrder;
  }

  @Override
  public MutableGraph<Integer> createGraph() {
    return GraphBuilder.directed()

        });
  }

  private final boolean allowsSelfLoops;
  private final ElementOrder<Integer> incidentEdgeOrder;

  public StandardMutableDirectedGraphTest(
      boolean allowsSelfLoops, ElementOrder<Integer> incidentEdgeOrder) {
    this.allowsSelfLoops = allowsSelfLoops;
    this.incidentEdgeOrder = incidentEdgeOrder;
  }

  @Override
  public MutableGraph<Integer> createGraph() {
    return GraphBuilder.directed()

    assertThat(immutableValueGraph.incidentEdgeOrder()).isEqualTo(ElementOrder.stable());
  }

  @Test
  public void incidentEdgeOrder_fromUnorderedGraph_stable() {
    ImmutableValueGraph<String, Integer> immutableValueGraph =
        ImmutableValueGraph.copyOf(
            ValueGraphBuilder.directed()
                .incidentEdgeOrder(ElementOrder.unordered())
                .<String, Integer>build());

  private UndirectedGraphConnections(Map<N, V> adjacentNodeValues) {
    this.adjacentNodeValues = checkNotNull(adjacentNodeValues);
  }

  static <N, V> UndirectedGraphConnections<N, V> of(ElementOrder<N> incidentEdgeOrder) {
    switch (incidentEdgeOrder.type()) {
      case UNORDERED:
        return new UndirectedGraphConnections<>(
            new HashMap<N, V>(INNER_CAPACITY, INNER_LOAD_FACTOR));
      case STABLE: