assertThat(hasCycle(undirectedGraph)).isFalse();
  }

  @Test
  public void hasCycle_isolatedNodes() {
    for (MutableGraph<Integer> graph : graphsToTest) {
      graph.addNode(1);
      graph.addNode(2);
    }
    assertThat(hasCycle(directedGraph)).isFalse();
    assertThat(hasCycle(undirectedGraph)).isFalse();
  }

  @Test
  public void hasCycle_oneEdge() {

   * <p><b>Nodes must be unique</b>, just as {@code Map} keys must be. They must also be non-null.
   *
   * @return {@code true} if the network was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean addNode(N node);

  /**
   * Adds {@code edge} connecting {@code nodeU} to {@code nodeV}.
   *
   * <p>If the graph is directed, {@code edge} will be directed in this graph; otherwise, it will be
   * undirected.
   *

      24, 26, 23, 26, 27, 26, 26, 27, 27, 27, 27, 27, 28, 27, 27, 27, 27, 27, 26,
    )

  private val root = Node()

  init {
    for (i in CODE_BIT_COUNTS.indices) {
      addCode(i, CODES[i], CODE_BIT_COUNTS[i].toInt())
    }
  }

  @Throws(IOException::class)
  fun encode(
    source: ByteString,
    sink: BufferedSink,
  ) {
    var accumulator = 0L

      assertThat(network.nodes()).isEmpty();
      assertThat(network.edges()).isEmpty();
      AbstractNetworkTest.validateNetwork(network);

      while (network.nodes().size() < NUM_NODES) {
        network.addNode(gen.nextInt(NODE_POOL_SIZE));
      }
      ArrayList<Integer> nodeList = new ArrayList<>(network.nodes());
      for (int i = 0; i < NUM_EDGES; ++i) {
        // Parallel edges are allowed, so this should always succeed.

    }
    throw new IllegalStateException("Unexpected edge type: " + edgeType);
  }

  @Test
  public void equivalent_nodeSetsDiffer() {
    network.addNode(N1);

    MutableNetwork<Integer, String> g2 = createNetwork(edgeType);
    g2.addNode(N2);

    assertThat(network).isNotEqualTo(g2);
  }

  // Node sets are the same, but edge sets differ.
  @Test
  public void equivalent_edgeSetsDiffer() {

    }
    throw new IllegalStateException("Unexpected edge type: " + edgeType);
  }

  @Test
  public void equivalent_nodeSetsDiffer() {
    network.addNode(N1);

    MutableNetwork<Integer, String> g2 = createNetwork(edgeType);
    g2.addNode(N2);

    assertThat(network).isNotEqualTo(g2);
  }

  // Node sets are the same, but edge sets differ.
  @Test
  public void equivalent_edgeSetsDiffer() {

        return termsQuery;
    }

    protected IdsQueryBuilder regIdsQ(Collection<String> values) {
        checkEsInvalidQueryCollection("_id", values);
        IdsQueryBuilder idsQuery = QueryBuilders.idsQuery().addIds(values.toArray(new String[values.size()]));
        regQ(idsQuery);
        return idsQuery;
    }

    protected MatchQueryBuilder regMatchQ(String name, Object value) {
        checkEsInvalidQuery(name, value);

   * element, or at the end of the list if {@code nextSibling} is null. Note: if {@code nextSibling}
   * is specified, it MUST be for a node for the same {@code key}!
   */
  @CanIgnoreReturnValue
  private Node<K, V> addNode(
      @ParametricNullness K key,
      @ParametricNullness V value,
      @CheckForNull Node<K, V> nextSibling) {
    Node<K, V> node = new Node<>(key, value);
    if (head == null) { // empty list

        return termsQuery;
    }

    protected IdsQueryBuilder regIdsQ(Collection<String> values) {
        checkEsInvalidQueryCollection("_id", values);
        IdsQueryBuilder idsQuery = QueryBuilders.idsQuery().addIds(values.toArray(new String[values.size()]));
        regQ(idsQuery);
        return idsQuery;
    }

    protected MatchQueryBuilder regMatchQ(String name, Object value) {
        checkEsInvalidQuery(name, value);

        return termsQuery;
    }

    protected IdsQueryBuilder regIdsQ(Collection<String> values) {
        checkEsInvalidQueryCollection("_id", values);
        IdsQueryBuilder idsQuery = QueryBuilders.idsQuery().addIds(values.toArray(new String[values.size()]));
        regQ(idsQuery);
        return idsQuery;
    }

    protected MatchQueryBuilder regMatchQ(String name, Object value) {
        checkEsInvalidQuery(name, value);