}
      };
    }

    @Override
    public int inDegree(N node) {
      return delegate().outDegree(node); // transpose
    }

    @Override
    public int outDegree(N node) {
      return delegate().inDegree(node); // transpose
    }

    @Override
    public boolean hasEdgeConnecting(N nodeU, N nodeV) {

  /**
   * Returns the count of {@code node}'s incident edges, counting self-loops twice (equivalently,
   * the number of times an edge touches {@code node}).
   *
   * <p>For directed graphs, this is equal to {@code inDegree(node) + outDegree(node)}.
   *
   * <p>For undirected graphs, this is equal to {@code incidentEdges(node).size()} + (number of
   * self-loops incident to {@code node}).
   *

  /**
   * Returns the count of {@code node}'s incident edges, counting self-loops twice (equivalently,
   * the number of times an edge touches {@code node}).
   *
   * <p>For directed graphs, this is equal to {@code inDegree(node) + outDegree(node)}.
   *
   * <p>For undirected graphs, this is equal to {@code incidentEdges(node).size()} + (number of
   * self-loops incident to {@code node}).
   *

      int selfLoopCount = (allowsSelfLoops() && neighbors.contains(node)) ? 1 : 0;
      return IntMath.saturatedAdd(neighbors.size(), selfLoopCount);
    }
  }

  @Override
  public int inDegree(N node) {
    return isDirected() ? predecessors(node).size() : degree(node);
  }

  @Override
  public int outDegree(N node) {
    return isDirected() ? successors(node).size() : degree(node);
  }

    } else {
      return IntMath.saturatedAdd(incidentEdges(node).size(), edgesConnecting(node, node).size());
    }
  }

  @Override
  public int inDegree(N node) {
    return isDirected() ? inEdges(node).size() : degree(node);
  }

  @Override
  public int outDegree(N node) {
    return isDirected() ? outEdges(node).size() : degree(node);
  }

   * self-loops twice (equivalently, the number of times an edge touches {@code node}).
   *
   * <p>For directed networks, this is equal to {@code inDegree(node) + outDegree(node)}.
   *
   * <p>For undirected networks, this is equal to {@code incidentEdges(node).size()} + (number of
   * self-loops incident to {@code node}).
   *

    assertThat(graph.incidentEdges(N2)).containsExactly(expectedEndpoints);
  }

  @Test
  public void inDegree_oneEdge() {
    putEdge(N1, N2);
    assertThat(graph.inDegree(N2)).isEqualTo(1);
    // Edge direction handled correctly
    assertThat(graph.inDegree(N1)).isEqualTo(0);
  }

  @Test
  public void outDegree_oneEdge() {
    putEdge(N1, N2);
    assertThat(graph.outDegree(N1)).isEqualTo(1);

    assertThat(graph.incidentEdges(N2)).containsExactly(expectedEndpoints);
  }

  @Test
  public void inDegree_oneEdge() {
    putEdge(N1, N2);
    assertThat(graph.inDegree(N2)).isEqualTo(1);
    assertThat(graph.inDegree(N1)).isEqualTo(1);
  }

  @Test
  public void outDegree_oneEdge() {
    putEdge(N1, N2);
    assertThat(graph.outDegree(N1)).isEqualTo(1);

    assertThat(graph.incidentEdges(N2)).containsExactly(expectedEndpoints);
  }

  @Test
  public void inDegree_oneEdge() {
    putEdge(N1, N2);
    assertThat(graph.inDegree(N2)).isEqualTo(1);
    assertThat(graph.inDegree(N1)).isEqualTo(1);
  }

  @Test
  public void outDegree_oneEdge() {
    putEdge(N1, N2);
    assertThat(graph.outDegree(N1)).isEqualTo(1);

    assertEdgeNotInGraphErrorMessage(e);
  }

  @Test
  public void inDegree_oneEdge() {
    addEdge(N1, N2, E12);
    assertThat(network.inDegree(N2)).isEqualTo(1);
    // Edge direction handled correctly
    assertThat(network.inDegree(N1)).isEqualTo(0);
  }

  @Test
  public void outDegree_oneEdge() {
    addEdge(N1, N2, E12);
    assertThat(network.outDegree(N1)).isEqualTo(1);