*/
@Beta
@DoNotMock
public final class GraphBuilder<N> extends AbstractGraphBuilder<N> {

  /** Creates a new instance with the specified edge directionality. */
  private GraphBuilder(boolean directed) {
    super(directed);
  }

  /** Returns a {@link GraphBuilder} for building directed graphs. */
  public static GraphBuilder<Object> directed() {
    return new GraphBuilder<>(true);
  }

  @Test
  public void transitiveClosure_directedGraph() {
    MutableGraph<Integer> directedGraph = GraphBuilder.directed().allowsSelfLoops(false).build();
    directedGraph.putEdge(N1, N2);
    directedGraph.putEdge(N1, N3);
    directedGraph.putEdge(N2, N3);
    directedGraph.addNode(N4);

    MutableGraph<Integer> expectedClosure = GraphBuilder.directed().allowsSelfLoops(true).build();
    expectedClosure.putEdge(N1, N1);

  // Node order tests

  @Test
  public void nodeOrder_none() {
    MutableGraph<Integer> graph = GraphBuilder.directed().nodeOrder(unordered()).build();

    assertThat(graph.nodeOrder()).isEqualTo(unordered());
  }

  @Test
  public void nodeOrder_insertion() {
    MutableGraph<Integer> graph = GraphBuilder.directed().nodeOrder(insertion()).build();

    addNodes(graph);

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

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

  private static void testGraphMutation(GraphBuilder<? super Integer> graphBuilder) {
    Random gen = new Random(42); // Fixed seed so test results are deterministic.

  }

  /**
   * Tests that the ImmutableGraph.Builder doesn't change when the creating GraphBuilder changes.
   */
  @Test
  @SuppressWarnings("CheckReturnValue")
  public void immutableGraphBuilder_copiesGraphBuilder() {
    GraphBuilder<String> graphBuilder =
        GraphBuilder.directed()
            .allowsSelfLoops(true)
            .<String>nodeOrder(ElementOrder.<String>natural());

  }

  /**
   * Tests that the ImmutableGraph.Builder doesn't change when the creating GraphBuilder changes.
   */
  @Test
  @SuppressWarnings("CheckReturnValue")
  public void immutableGraphBuilder_copiesGraphBuilder() {
    GraphBuilder<String> graphBuilder =
        GraphBuilder.directed()
            .allowsSelfLoops(true)
            .<String>nodeOrder(ElementOrder.<String>natural());

  private static final AbstractGraphBuilder<?> graphBuilderA =
      GraphBuilder.directed().expectedNodeCount(10);
  private static final AbstractGraphBuilder<?> graphBuilderB =
      ValueGraphBuilder.directed().allowsSelfLoops(true).expectedNodeCount(16);

  private static final ImmutableGraph<String> IMMUTABLE_GRAPH_A =
      GraphBuilder.directed().<String>immutable().addNode("A").build();

  // TODO(user): Move these to a more appropriate location in the test suite.

  @Test
  public void endpointPair_directedGraph() {
    MutableGraph<Integer> directedGraph = GraphBuilder.directed().allowsSelfLoops(true).build();
    directedGraph.addNode(N0);
    directedGraph.putEdge(N1, N2);
    directedGraph.putEdge(N2, N1);
    directedGraph.putEdge(N1, N3);
    directedGraph.putEdge(N4, N4);

  public void immutableValueGraphBuilder_copiesGraphBuilder() {
    ValueGraphBuilder<String, Object> graphBuilder =
        ValueGraphBuilder.directed()
            .allowsSelfLoops(true)
            .<String>nodeOrder(ElementOrder.<String>natural());
    ImmutableValueGraph.Builder<String, Integer> immutableValueGraphBuilder =
        graphBuilder.<String, Integer>immutable();

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

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

  private static void testGraphMutation(GraphBuilder<? super Integer> graphBuilder) {
    Random gen = new Random(42); // Fixed seed so test results are deterministic.