graph.addNode(node4);
    graph.addNode(node2);
    graph.addNode(node6);
    graph.addNode(node8);

    assertThat(graph.nodeOrder().comparator()).isEqualTo(Ordering.natural());
    assertThat(graph.nodes()).containsExactly(node2, node4, node6, node8).inOrder();
  }

  private static void addNodes(MutableGraph<Integer> graph) {
    graph.addNode(3);
    graph.addNode(1);

      NetworkBuilder.directed().<String, String>immutable().addNode("A").build();
  private static final ImmutableNetwork<String, String> IMMUTABLE_NETWORK_B =
      NetworkBuilder.directed().<String, String>immutable().addNode("B").build();

  public PackageSanityTests() {
    MutableNetwork<String, String> mutableNetworkA = NetworkBuilder.directed().build();
    mutableNetworkA.addNode("a");

  }

  @Test
  public void edgesConnecting_disconnectedNodes() {
    addNode(N1);
    addNode(N2);
    assertThat(network.edgesConnecting(N1, N2)).isEmpty();
  }

  @Test
  public void edgesConnecting_nodesNotInGraph() {
    addNode(N1);
    addNode(N2);
    assertNodeNotInGraphErrorMessage(
        assertThrows(

    }
  }

  @Override
  @Test
  public void edgesConnecting_checkReturnedSetMutability() {
    assume().that(graphIsMutable()).isTrue();

    addNode(N1);
    addNode(N2);
    Set<String> edgesConnecting = network.edgesConnecting(N1, N2);
    assertThrows(UnsupportedOperationException.class, () -> edgesConnecting.add(E23));
    addEdge(N1, N2, E12);

    }
  }

  @Override
  @Test
  public void edgesConnecting_checkReturnedSetMutability() {
    assume().that(graphIsMutable()).isTrue();

    addNode(N1);
    addNode(N2);
    Set<String> edgesConnecting = network.edgesConnecting(N1, N2);
    assertThrows(UnsupportedOperationException.class, () -> edgesConnecting.add(E23));
    addEdge(N1, N2, E12);

    assertThrows(UnsupportedOperationException.class, () -> nodes.add(N2));
    addNode(N1);
    assertThat(graph.nodes()).containsExactlyElementsIn(nodes);
  }

  @Override
  @Test
  public void adjacentNodes_checkReturnedSetMutability() {
    assume().that(graphIsMutable()).isTrue();

    addNode(N1);
    Set<Integer> adjacentNodes = graph.adjacentNodes(N1);

      assertThat(network.adjacentEdges(E12)).containsExactlyElementsIn(adjacentEdges);
    }
  }

  @Override
  @Test
  public void edgesConnecting_checkReturnedSetMutability() {
    addNode(N1);
    addNode(N2);
    Set<String> edgesConnecting = network.edgesConnecting(N1, N2);
    assertThrows(UnsupportedOperationException.class, () -> edgesConnecting.add(E23));
    addEdge(N1, N2, E12);

    }

    /*
     * (non-Javadoc)
     *
     * @see
     * org.codelibs.fess.crawler.rule.RuleManager#addRule(org.codelibs.fess.crawler.rule.Rule)
     */
    @Override
    public void addRule(final Rule rule) {
        ruleList.add(rule);
    }

    @Override
    public void addRule(final int index, final Rule rule) {
        ruleList.add(index, rule);
    }

    /*
     * (non-Javadoc)
     *

    assertThrows(UnsupportedOperationException.class, () -> nodes.add(N2));
    addNode(N1);
    assertThat(graph.nodes()).containsExactlyElementsIn(nodes);
  }

  @Override
  @Test
  public void adjacentNodes_checkReturnedSetMutability() {
    assume().that(graphIsMutable()).isTrue();

    addNode(N1);
    Set<Integer> adjacentNodes = graph.adjacentNodes(N1);

    @Resource
    protected CrawlerContainer crawlerContainer;

    public void register(final int index) {
        final RuleManager ruleManager = crawlerContainer.getComponent("ruleManager");
        ruleManager.addRule(index, this);
    }

    @Override
    public String getRuleId() {
        return ruleId;
    }

    public void setRuleId(final String ruleId) {
        this.ruleId = ruleId;
    }

    @Override