Graph<Integer> asGraph = graph.asGraph();
    AbstractGraphTest.validateGraph(asGraph);
    assertThat(graph.nodes()).isEqualTo(asGraph.nodes());
    assertThat(graph.edges()).isEqualTo(asGraph.edges());
    assertThat(graph.nodeOrder()).isEqualTo(asGraph.nodeOrder());
    assertThat(graph.incidentEdgeOrder()).isEqualTo(asGraph.incidentEdgeOrder());

    Graph<Integer> asGraph = graph.asGraph();
    AbstractGraphTest.validateGraph(asGraph);
    assertThat(graph.nodes()).isEqualTo(asGraph.nodes());
    assertThat(graph.edges()).isEqualTo(asGraph.edges());
    assertThat(graph.nodeOrder()).isEqualTo(asGraph.nodeOrder());
    assertThat(graph.incidentEdgeOrder()).isEqualTo(asGraph.incidentEdgeOrder());

    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) {

      }

      @Override
      public Graph<N> asGraph() {
        if (AbstractBaseGraph.this instanceof Graph) {
          return (Graph<N>) AbstractBaseGraph.this;
        } else if (AbstractBaseGraph.this instanceof ValueGraph) {
          return ((ValueGraph<N, ?>) AbstractBaseGraph.this).asGraph();
        }
        throw new UnsupportedOperationException(

public abstract class AbstractValueGraph<N, V> extends AbstractBaseGraph<N>
    implements ValueGraph<N, V> {
  /** Constructor for use by subclasses. */
  public AbstractValueGraph() {}

  @Override
  public Graph<N> asGraph() {
    return new AbstractGraph<N>() {
      @Override
      public Set<N> nodes() {
        return AbstractValueGraph.this.nodes();
      }

      @Override
      public Set<EndpointPair<N>> edges() {

  }

  @Test
  public void edges_containsOrderMismatch() {
    addEdge(N1, N2, E12);
    assertThat(network.asGraph().edges()).doesNotContain(ENDPOINTS_N2N1);
    assertThat(network.asGraph().edges()).doesNotContain(ENDPOINTS_N1N2);
  }

  @Test
  public void edgesConnecting_orderMismatch() {
    addEdge(N1, N2, E12);
    IllegalArgumentException e =

    assertThat(asNetwork.edgeOrder()).isEqualTo(ElementOrder.unordered());
    assertThat(asNetwork.allowsParallelEdges()).isFalse();
    assertThat(asNetwork.asGraph()).isEqualTo(graph);

    Set<EndpointPair<N>> allEndpointPairs = new HashSet<>();

    for (N node : sanityCheckSet(graph.nodes())) {
      assertThat(nodeString).contains(node.toString());

    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) {

 * @since 20.0
 */
@Beta
public abstract class AbstractNetwork<N, E> implements Network<N, E> {
  /** Constructor for use by subclasses. */
  public AbstractNetwork() {}

  @Override
  public Graph<N> asGraph() {
    return new AbstractGraph<N>() {
      @Override
      public Set<N> nodes() {
        return AbstractNetwork.this.nodes();
      }

      @Override
      public Set<EndpointPair<N>> edges() {

 * @since 20.0
 */
@Beta
public abstract class AbstractNetwork<N, E> implements Network<N, E> {
  /** Constructor for use by subclasses. */
  public AbstractNetwork() {}

  @Override
  public Graph<N> asGraph() {
    return new AbstractGraph<N>() {
      @Override
      public Set<N> nodes() {
        return AbstractNetwork.this.nodes();
      }

      @Override
      public Set<EndpointPair<N>> edges() {