assertThat(graph.inDegree(N1)).isEqualTo(1);
  }

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

  @Test
  public void hasEdgeConnecting_correct() {
    putEdge(N1, N2);
    assertThat(graph.hasEdgeConnecting(EndpointPair.unordered(N1, N2))).isTrue();

    assertThat(network.inDegree(N1)).isEqualTo(0);
  }

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

  @Test
  public void edges_selfLoop() {
    assume().that(network.allowsSelfLoops()).isTrue();

    addEdge(N1, N1, E11);

    assertThat(network.inDegree(N1)).isEqualTo(0);
  }

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

  @Test
  public void edges_selfLoop() {
    assume().that(network.allowsSelfLoops()).isTrue();

    addEdge(N1, N1, E11);

    assertThat(graph.inDegree(N1)).isEqualTo(1);
  }

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

  @Test
  public void hasEdgeConnecting_correct() {
    putEdge(N1, N2);
    assertThat(graph.hasEdgeConnecting(EndpointPair.unordered(N1, N2))).isTrue();

      }

      @Override
      public int inDegree(N node) {
        return AbstractValueGraph.this.inDegree(node);
      }

      @Override
      public int outDegree(N node) {
        return AbstractValueGraph.this.outDegree(node);
      }
    };
  }

  @Override
  public final boolean equals(@CheckForNull Object obj) {
    if (obj == this) {
      return true;
    }

    assertThat(network.inDegree(N1)).isEqualTo(1);
  }

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

  @Test
  public void edges_selfLoop() {
    assume().that(network.allowsSelfLoops()).isTrue();

    addEdge(N1, N1, E11);

      }

      @Override
      public int inDegree(N node) {
        return AbstractValueGraph.this.inDegree(node);
      }

      @Override
      public int outDegree(N node) {
        return AbstractValueGraph.this.outDegree(node);
      }
    };
  }

  @Override
  public Optional<V> edgeValue(N nodeU, N nodeV) {
    return Optional.ofNullable(edgeValueOrDefault(nodeU, nodeV, null));
  }

      if (graph.isDirected()) {
        assertThat(graph.degree(node)).isEqualTo(graph.inDegree(node) + graph.outDegree(node));
        assertThat(graph.predecessors(node)).hasSize(graph.inDegree(node));
        assertThat(graph.successors(node)).hasSize(graph.outDegree(node));
      } else {
        int selfLoopCount = graph.adjacentNodes(node).contains(node) ? 1 : 0;

    AbstractGraphTest.validateGraph(transpose);

    for (Integer node : directedGraph.nodes()) {
      assertThat(directedGraph.inDegree(node)).isSameInstanceAs(transpose.outDegree(node));
      assertThat(directedGraph.outDegree(node)).isSameInstanceAs(transpose.inDegree(node));
    }

    assertThat(transpose.successors(N1)).doesNotContain(N2);
    directedGraph.putEdge(N2, N1);
    // View should be updated.

    assertThat(network.inDegree(N1)).isEqualTo(1);
  }

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

  @Test
  public void edges_selfLoop() {
    assume().that(network.allowsSelfLoops()).isTrue();

    addEdge(N1, N1, E11);