ImmutableNetwork.copyOf(NetworkBuilder.directed().<String, String>build());
    Network<String, String> network2 = ImmutableNetwork.copyOf(network1);

    assertThat(network2).isSameInstanceAs(network1);
  }

  @Test
  public void edgesConnecting_directed() {
    MutableNetwork<String, String> mutableNetwork =
        NetworkBuilder.directed().allowsSelfLoops(true).build();

  }

  @Test
  public void incidentEdgeOrder_unordered() {
    graph = ValueGraphBuilder.directed().incidentEdgeOrder(ElementOrder.unordered()).build();
    assertThat(graph.incidentEdgeOrder()).isEqualTo(ElementOrder.unordered());
  }

  @Test
  public void incidentEdgeOrder_stable() {
    graph = ValueGraphBuilder.directed().incidentEdgeOrder(ElementOrder.stable()).build();

  }

  @Test
  public void incidentEdgeOrder_unordered() {
    graph = ValueGraphBuilder.directed().incidentEdgeOrder(ElementOrder.unordered()).build();
    assertThat(graph.incidentEdgeOrder()).isEqualTo(ElementOrder.unordered());
  }

  @Test
  public void incidentEdgeOrder_stable() {
    graph = ValueGraphBuilder.directed().incidentEdgeOrder(ElementOrder.stable()).build();

  private static final int NUM_EDGES = 1000;
  private static final int NODE_POOL_SIZE = 1000; // must be >> NUM_NODES

  @Test
  public void directedGraph() {
    testGraphMutation(GraphBuilder.directed());
  }

  @Test
  public void undirectedGraph() {
    testGraphMutation(GraphBuilder.undirected());
  }

  private static void testGraphMutation(GraphBuilder<? super Integer> graphBuilder) {

  private static final int NUM_EDGES = 100;
  private static final int NODE_POOL_SIZE = 1000; // must be >> NUM_NODES

  @Test
  public void directedNetwork() {
    testNetworkMutation(NetworkBuilder.directed());
  }

  @Test
  public void undirectedNetwork() {
    testNetworkMutation(NetworkBuilder.undirected());
  }

  private static void testNetworkMutation(NetworkBuilder<? super Integer, Object> networkBuilder) {

  private static final int NUM_EDGES = 1000;
  private static final int NODE_POOL_SIZE = 1000; // must be >> NUM_NODES

  @Test
  public void directedGraph() {
    testGraphMutation(GraphBuilder.directed());
  }

  @Test
  public void undirectedGraph() {
    testGraphMutation(GraphBuilder.undirected());
  }

  private static void testGraphMutation(GraphBuilder<? super Integer> graphBuilder) {

  Network<Integer, String> directedNetwork;
  Network<Integer, String> undirectedNetwork;

  @Before
  public void init() {
    MutableGraph<Integer> mutableDirectedGraph =
        GraphBuilder.directed().allowsSelfLoops(true).build();
    MutableGraph<Integer> mutableUndirectedGraph =
        GraphBuilder.undirected().allowsSelfLoops(true).build();
    graphsToTest = ImmutableList.of(mutableDirectedGraph, mutableUndirectedGraph);

   * node map.
   */
  StandardValueGraph(
      AbstractGraphBuilder<? super N> builder,
      Map<N, GraphConnections<N, V>> nodeConnections,
      long edgeCount) {
    this.isDirected = builder.directed;
    this.allowsSelfLoops = builder.allowsSelfLoops;
    this.nodeOrder = builder.nodeOrder.cast();
    // Prefer the heavier "MapRetrievalCache" for nodes if lookup is expensive.
    this.nodeConnections =

  private static final int NUM_EDGES = 100;
  private static final int NODE_POOL_SIZE = 1000; // must be >> NUM_NODES

  @Test
  public void directedNetwork() {
    testNetworkMutation(NetworkBuilder.directed());
  }

  @Test
  public void undirectedNetwork() {
    testNetworkMutation(NetworkBuilder.undirected());
  }

  private static void testNetworkMutation(NetworkBuilder<? super Integer, Object> networkBuilder) {

 * iteration order guarantees.
 *
 * <p>Example usage:
 *
 * {@snippet :
 * MutableGraph<Integer> graph =
 *     GraphBuilder.directed().nodeOrder(ElementOrder.<Integer>natural()).build();
 * }
 *
 * @author Joshua O'Madadhain
 * @since 20.0
 */
@Immutable
public final class ElementOrder<T> {
  private final Type type;