return checkNotNull(graph);
  }

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

  @Override
  public ImmutableGraph<N> asGraph() {
    return new ImmutableGraph<>(this); // safe because the view is effectively immutable
  }

  private static <N, V> ImmutableMap<N, GraphConnections<N, V>> getNodeConnections(
      ValueGraph<N, V> graph) {

  @Parameters(name = "allowsSelfLoops={0}")
  public static Collection<Object[]> parameters() {
    return Arrays.asList(new Object[][] {{false}, {true}});
  }

  private final boolean allowsSelfLoops;
  private ImmutableGraph.Builder<Integer> graphBuilder;

  public StandardImmutableUndirectedGraphTest(boolean allowsSelfLoops) {
    this.allowsSelfLoops = allowsSelfLoops;
  }

  @Override
  public Graph<Integer> createGraph() {

   */
  @Deprecated
  public static <N, E> ImmutableNetwork<N, E> copyOf(ImmutableNetwork<N, E> network) {
    return checkNotNull(network);
  }

  @Override
  public ImmutableGraph<N> asGraph() {
    return new ImmutableGraph<>(super.asGraph()); // safe because the view is effectively immutable
  }

  private static <N, E> Map<N, NetworkConnections<N, E>> getNodeConnections(Network<N, E> network) {

    mutableNetwork.addNode("A");
    ImmutableNetwork<String, Integer> immutableNetwork = ImmutableNetwork.copyOf(mutableNetwork);

    assertThat(immutableNetwork.asGraph()).isInstanceOf(ImmutableGraph.class);
    assertThat(immutableNetwork).isNotInstanceOf(MutableNetwork.class);
    assertThat(immutableNetwork).isEqualTo(mutableNetwork);

    mutableNetwork.addNode("B");

    mutableValueGraph.addNode("A");
    ImmutableValueGraph<String, Integer> immutableValueGraph =
        ImmutableValueGraph.copyOf(mutableValueGraph);

    assertThat(immutableValueGraph.asGraph()).isInstanceOf(ImmutableGraph.class);
    assertThat(immutableValueGraph).isNotInstanceOf(MutableValueGraph.class);
    assertThat(immutableValueGraph).isEqualTo(mutableValueGraph);

    mutableValueGraph.addNode("B");

    mutableNetwork.addNode("A");
    ImmutableNetwork<String, Integer> immutableNetwork = ImmutableNetwork.copyOf(mutableNetwork);

    assertThat(immutableNetwork.asGraph()).isInstanceOf(ImmutableGraph.class);
    assertThat(immutableNetwork).isNotInstanceOf(MutableNetwork.class);
    assertThat(immutableNetwork).isEqualTo(mutableNetwork);

    mutableNetwork.addNode("B");

    mutableValueGraph.addNode("A");
    ImmutableValueGraph<String, Integer> immutableValueGraph =
        ImmutableValueGraph.copyOf(mutableValueGraph);

    assertThat(immutableValueGraph.asGraph()).isInstanceOf(ImmutableGraph.class);
    assertThat(immutableValueGraph).isNotInstanceOf(MutableValueGraph.class);
    assertThat(immutableValueGraph).isEqualTo(mutableValueGraph);

    mutableValueGraph.addNode("B");

   *
   * @since 33.1.0 (present with return type {@code Graph} since 20.0)
   */
  // TODO(b/31438252): Consider potential optimizations for this algorithm.
  public static <N> ImmutableGraph<N> transitiveClosure(Graph<N> graph) {
    ImmutableGraph.Builder<N> transitiveClosure =
        GraphBuilder.from(graph).allowsSelfLoops(true).<N>immutable();
    // Every node is, at a minimum, reachable from itself. Since the resulting transitive closure

 * graph.putEdgeValue("San Jose", "San Jose", 0.0);
 * graph.putEdgeValue("San Francisco", "San Jose", 48.4);
 *
 * // Building an immutable value graph
 * ImmutableValueGraph<String, Double> immutableGraph =
 *     ValueGraphBuilder.undirected()
 *         .allowsSelfLoops(true)
 *         .<String, Double>immutable()
 *         .putEdgeValue("San Francisco", "San Francisco", 0.0)

    validateGraph(graph);
  }

  static <N> void validateGraph(Graph<N> graph) {
    assertStronglyEquivalent(graph, Graphs.copyOf(graph));
    assertStronglyEquivalent(graph, ImmutableGraph.copyOf(graph));

    String graphString = graph.toString();
    assertThat(graphString).contains("isDirected: " + graph.isDirected());
    assertThat(graphString).contains("allowsSelfLoops: " + graph.allowsSelfLoops());