HONDA,
    POODLE,
  }

  public void testGetIfPresent() {
    assertThat(Enums.getIfPresent(TestEnum.class, "CHEETO")).hasValue(TestEnum.CHEETO);
    assertThat(Enums.getIfPresent(TestEnum.class, "HONDA")).hasValue(TestEnum.HONDA);
    assertThat(Enums.getIfPresent(TestEnum.class, "POODLE")).hasValue(TestEnum.POODLE);

    assertThat(Enums.getIfPresent(TestEnum.class, "CHEETO")).isPresent();

    graph.putEdgeValue(1, 2, "A");
    assertThat(graph.edgeValue(EndpointPair.unordered(1, 2))).hasValue("A");
  }

  @Test
  public void edgeValue_undirected_backwards() {
    graph = ValueGraphBuilder.undirected().build();
    graph.putEdgeValue(1, 2, "A");
    assertThat(graph.edgeValue(EndpointPair.unordered(2, 1))).hasValue("A");
  }

  @Test
  public void edgeValue_undirected_mismatch() {

  }

  public void testTryFind() {
    Iterable<String> list = newArrayList("cool", "pants");
    assertThat(tryFind(list, equalTo("cool"))).hasValue("cool");
    assertThat(tryFind(list, equalTo("pants"))).hasValue("pants");
    assertThat(tryFind(list, Predicates.alwaysTrue())).hasValue("cool");
    assertThat(tryFind(list, Predicates.alwaysFalse())).isAbsent();
    assertCanIterateAgain(list);
  }

    Iterator<String> iterator = list.iterator();
    assertThat(tryFind(iterator, equalTo("cool"))).hasValue("cool");
  }

  public void testTryFind_lastElement() {
    Iterable<String> list = Lists.newArrayList("cool", "pants");
    Iterator<String> iterator = list.iterator();
    assertThat(tryFind(iterator, equalTo("pants"))).hasValue("pants");
  }

  public void testTryFind_alwaysTrue() {

    }

    directedGraph.addEdge(N2, N1, E21);
    // View should be updated.
    assertThat(transpose.edgesConnecting(N1, N2)).containsExactly(E21);
    assertThat(transpose.edgeConnecting(N1, N2)).hasValue(E21);
    assertThat(transpose.edgeConnectingOrNull(N1, N2)).isEqualTo(E21);
    AbstractNetworkTest.validateNetwork(transpose);
  }

  @Test
  public void inducedSubgraph_graph() {