assertThat(iia.indexOf(1)).isEqualTo(0);
    assertThat(iia.indexOf(8)).isEqualTo(5);
    assertThat(iia.indexOf(4)).isEqualTo(-1);
    assertThat(ImmutableDoubleArray.of(13).indexOf(13)).isEqualTo(0);
    assertThat(ImmutableDoubleArray.of().indexOf(21)).isEqualTo(-1);
    assertThat(iia.subArray(1, 5).indexOf(1)).isEqualTo(0);
  }

  public void testIndexOf_specialValues() {

    assertThat(emptyAccumulator.count()).isEqualTo(0);
    assertThat(emptyAccumulatorByAddAllEmptyIterable.count()).isEqualTo(0);
    assertThat(emptyAccumulatorByAddAllEmptyStats.count()).isEqualTo(0);
    assertThat(oneValueAccumulator.count()).isEqualTo(1);
    assertThat(oneValueAccumulatorByAddAllEmptyStats.count()).isEqualTo(1);
    assertThat(twoValuesAccumulator.count()).isEqualTo(2);

    assertThat(iia.indexOf(1)).isEqualTo(0);
    assertThat(iia.indexOf(8)).isEqualTo(5);
    assertThat(iia.indexOf(4)).isEqualTo(-1);
    assertThat(ImmutableDoubleArray.of(13).indexOf(13)).isEqualTo(0);
    assertThat(ImmutableDoubleArray.of().indexOf(21)).isEqualTo(-1);
    assertThat(iia.subArray(1, 5).indexOf(1)).isEqualTo(0);
  }

  public void testIndexOf_specialValues() {

    Graph<Integer> copy = copyOf(directedGraph);
    assertThat(copy).isEqualTo(directedGraph);
  }

  @Test
  public void copyOf_undirectedGraph() {
    Graph<Integer> undirectedGraph = buildUndirectedGraph();

    Graph<Integer> copy = copyOf(undirectedGraph);
    assertThat(copy).isEqualTo(undirectedGraph);
  }

  @Test
  public void copyOf_directedValueGraph() {

    assertThat(iia.indexOf(1)).isEqualTo(0);
    assertThat(iia.indexOf(8)).isEqualTo(5);
    assertThat(iia.indexOf(4)).isEqualTo(-1);
    assertThat(ImmutableLongArray.of(13).indexOf(13)).isEqualTo(0);
    assertThat(ImmutableLongArray.of().indexOf(21)).isEqualTo(-1);
    assertThat(iia.subArray(1, 5).indexOf(1)).isEqualTo(0);
  }

  public void testLastIndexOf() {

        assertThat(endpointPair.source()).isEqualTo(endpointPair.adjacentNode(node));
        assertThat(endpointPair.target()).isEqualTo(node);
      }

      for (String outEdge : network.outEdges(node)) {
        EndpointPair<Integer> endpointPair = network.incidentNodes(outEdge);
        assertThat(endpointPair.source()).isEqualTo(node);
        assertThat(endpointPair.target()).isEqualTo(endpointPair.adjacentNode(node));
      }

    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);
    // Edge direction handled correctly
    assertThat(graph.outDegree(N2)).isEqualTo(0);
  }

  @Test

  }

  public void testMinMaxNatural() {
    assertThat(Comparators.min(1, 2)).isEqualTo(1);
    assertThat(Comparators.min(2, 1)).isEqualTo(1);
    assertThat(Comparators.max(1, 2)).isEqualTo(2);
    assertThat(Comparators.max(2, 1)).isEqualTo(2);
  }

  public void testMinMaxNatural_equalInstances() {
    Foo a = new Foo(1);
    Foo b = new Foo(1);

    assertThat(ordered.source()).isEqualTo("source");
    assertThat(ordered.target()).isEqualTo("target");
    assertThat(ordered.nodeU()).isEqualTo("source");
    assertThat(ordered.nodeV()).isEqualTo("target");
    assertThat(ordered.adjacentNode("source")).isEqualTo("target");
    assertThat(ordered.adjacentNode("target")).isEqualTo("source");
    assertThat(ordered.toString()).isEqualTo("<source -> target>");
  }

  @Test

    assertThat(ordered.source()).isEqualTo("source");
    assertThat(ordered.target()).isEqualTo("target");
    assertThat(ordered.nodeU()).isEqualTo("source");
    assertThat(ordered.nodeV()).isEqualTo("target");
    assertThat(ordered.adjacentNode("source")).isEqualTo("target");
    assertThat(ordered.adjacentNode("target")).isEqualTo("source");
    assertThat(ordered.toString()).isEqualTo("<source -> target>");
  }

  @Test