new Object[][] {
          {UNDIRECTED}, {DIRECTED},
        });
  }

  private final EdgeType edgeType;

  public DefaultNetworkImplementationsTest(EdgeType edgeType) {
    this.edgeType = edgeType;
  }

  @Before
  public void setUp() throws Exception {
    NetworkBuilder<Object, Object> builder =
        (edgeType == EdgeType.DIRECTED) ? NetworkBuilder.directed() : NetworkBuilder.undirected();

  }

  @Test
  public void incidentEdgeOrder_unordered() {
    graph = ValueGraphBuilder.directed().incidentEdgeOrder(ElementOrder.unordered()).build();
    assertThat(graph.incidentEdgeOrder()).isEqualTo(ElementOrder.unordered());
  }

  @Test
  public void incidentEdgeOrder_stable() {
    graph = ValueGraphBuilder.directed().incidentEdgeOrder(ElementOrder.stable()).build();

      case DIRECTED:
        return NetworkBuilder.directed().allowsSelfLoops(true).build();
    }
    throw new IllegalStateException("Unexpected edge type: " + edgeType);
  }

  private static EdgeType oppositeType(EdgeType edgeType) {
    switch (edgeType) {
      case UNDIRECTED:
        return EdgeType.DIRECTED;
      case DIRECTED:
        return EdgeType.UNDIRECTED;
    }

      case DIRECTED:
        return NetworkBuilder.directed().allowsSelfLoops(true).build();
    }
    throw new IllegalStateException("Unexpected edge type: " + edgeType);
  }

  private static EdgeType oppositeType(EdgeType edgeType) {
    switch (edgeType) {
      case UNDIRECTED:
        return EdgeType.DIRECTED;
      case DIRECTED:
        return EdgeType.UNDIRECTED;
    }

        doc.put("content", "xyz");

        // Without a real detector, this will throw NullPointerException
        try {
            languageHelper.updateDocument(doc);
            fail("Should throw NullPointerException without detector");
        } catch (NullPointerException e) {
            // Expected since we don't have a detector
        }
    }

    @Test
    public void test_updateDocument_emptyDoc() {

  }

  @Test
  public void testAdjacentNode_nodeNotIncident() {
    ImmutableList<MutableNetwork<Integer, String>> testNetworks =
        ImmutableList.of(
            NetworkBuilder.directed().<Integer, String>build(),
            NetworkBuilder.undirected().<Integer, String>build());
    for (MutableNetwork<Integer, String> network : testNetworks) {
      network.addEdge(1, 2, "1-2");

  }

  @Test
  public void testAdjacentNode_nodeNotIncident() {
    ImmutableList<MutableNetwork<Integer, String>> testNetworks =
        ImmutableList.of(
            NetworkBuilder.directed().<Integer, String>build(),
            NetworkBuilder.undirected().<Integer, String>build());
    for (MutableNetwork<Integer, String> network : testNetworks) {
      network.addEdge(1, 2, "1-2");

   * that edge to {@code value} (overwriting the existing value, if any).
   *
   * <p>If the graph is directed, the resultant edge will be directed; otherwise, it will be
   * undirected.
   *
   * <p>If this graph is directed, {@code endpoints} must be ordered.
   *
   * <p>Values do not have to be unique. However, values must be non-null.
   *

  /** 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);
  }

  /** Returns a {@link GraphBuilder} for building undirected graphs. */

   * also connect {@code nodeV} to {@code nodeU}.
   *
   * <p>If this graph is directed, {@code edge} will be directed in this graph; if it is undirected,
   * {@code edge} will be undirected in this graph.
   *
   * <p>If this graph is directed, {@code endpoints} must be ordered.
   *
   * <p><b>{@code edge} must be unique to this graph</b>, just as a {@code Map} key must be. It must