ArrayList<Object> edgeList = new ArrayList<>(network.edges());

      assertThat(network.nodes()).hasSize(NUM_NODES);
      assertThat(network.edges()).hasSize(NUM_EDGES);
      AbstractNetworkTest.validateNetwork(network);

      Collections.shuffle(edgeList, gen);
      int numEdgesToRemove = gen.nextInt(NUM_EDGES);
      for (int i = 0; i < numEdgesToRemove; ++i) {
        Object edge = edgeList.get(i);

    assertThat(edges).hasSize(2);
    assertThat(edges).contains(EndpointPair.unordered(N1, N1));
    assertThat(edges).contains(EndpointPair.unordered(N1, N2));
    assertThat(edges).contains(EndpointPair.unordered(N2, N1)); // equal to unordered(N1, N2)

    // ordered endpoints not compatible with undirected graph
    assertThat(edges).doesNotContain(EndpointPair.ordered(N1, N2));

    assertThat(edges).hasSize(2);
    assertThat(edges).contains(EndpointPair.unordered(N1, N1));
    assertThat(edges).contains(EndpointPair.unordered(N1, N2));
    assertThat(edges).contains(EndpointPair.unordered(N2, N1)); // equal to unordered(N1, N2)

    // ordered endpoints not compatible with undirected graph
    assertThat(edges).doesNotContain(EndpointPair.ordered(N1, N2));

    assertThat(network.edgeOrder())
        .isEqualTo(ElementOrder.sorted(Ordering.<String>natural().reverse()));
    assertThat(network.edges()).containsExactly("p", "i", "e").inOrder();
    assertThat(network.nodeOrder()).isEqualTo(ElementOrder.insertion()); // default
  }

  // Combined node and edge order tests

  @Test
  public void nodeOrderUnorderedAndEdgesSorted() {
    MutableNetwork<Integer, String> network =

    ValueGraphBuilder<N1, V1> castBuilder = cast();
    return new ImmutableValueGraph.Builder<>(castBuilder);
  }

  /**
   * Specifies whether the graph will allow self-loops (edges that connect a node to itself).
   * Attempting to add a self-loop to a graph that does not allow them will throw an {@link
   * UnsupportedOperationException}.
   *
   * <p>The default value is {@code false}.
   */

import org.apache.maven.api.services.model.*;

/**
 * Handles normalization of a model.
 *
 */
@Named
@Singleton
public class DefaultModelNormalizer implements ModelNormalizer {

    private DuplicateMerger merger = new DuplicateMerger();

    @Override
    public Model mergeDuplicates(Model model, ModelBuilderRequest request, ModelProblemCollector problems) {
        Model.Builder builder = Model.newBuilder(model);

        MetadataGraphEdge res;

        res = policy.apply(e1, e2);
        assertEquals("1.1", res.getVersion(), "Wrong depth edge selected");

        res = policy.apply(e1, e3);
        assertEquals("1.2", res.getVersion(), "Wrong version edge selected");
    }
    // ------------------------------------------------------------------------------------------

            List<String> cycle = visitCycle(graph, Collections.singleton(to), new HashMap<>(), new LinkedList<>());
            if (cycle != null) {
                // remove edge which introduced cycle
                throw new CycleDetectedException(
                        "Edge between '" + from + "' and '" + to + "' introduces to cycle in the graph", cycle);
            }
        }
    }

    private enum DfsState {
        VISITING,

        from.children.add(to);
        to.parents.add(from);
        List<String> cycle = findCycle(to);
        if (cycle != null) {
            // remove edge which introduced cycle
            removeEdge(from, to);
            throw new CycleDetectedException(
                    "Edge between '" + from.label + "' and '" + to.label + "' introduces to cycle in the graph", cycle);
        }
    }

    void removeEdge(Vertex from, Vertex to) {

 *
 */
@Deprecated
public interface GraphConflictResolver {
    String ROLE = GraphConflictResolver.class.getName();

    /**
     * Cleanses the supplied graph by leaving only one directed versioned edge\
     * between any two nodes, if multiple exists. Uses scope relationships, defined
     * in <code>ArtifactScopeEnum</code>
     *
     * @param graph the "dirty" graph to be simplified via conflict resolution