/** . */
  public void testDirectedGraph() {
    ListenableDirectedGraph<String, DefaultEdge> g =
        new ListenableDirectedGraph<String, DefaultEdge>(DefaultEdge.class);
    g.addVertex(V1);
    g.addVertex(V2);
    g.addVertex(V3);

    g.addEdge(V1, V2);

    ConnectivityInspector<String, DefaultEdge> inspector =
        new ConnectivityInspector<String, DefaultEdge>(g);
    g.addGraphListener(inspector);

    assertEquals(false, inspector.isGraphConnected());

    g.addEdge(V1, V3);

    assertEquals(true, inspector.isGraphConnected());
  }
  /** . */
  public void testIsGraphConnected() {
    Pseudograph<String, DefaultEdge> g = create();
    ConnectivityInspector<String, DefaultEdge> inspector =
        new ConnectivityInspector<String, DefaultEdge>(g);

    assertEquals(false, inspector.isGraphConnected());

    g.removeVertex(V4);
    inspector = new ConnectivityInspector<String, DefaultEdge>(g);
    assertEquals(true, inspector.isGraphConnected());

    g.removeVertex(V1);
    assertEquals(1, g.edgeSet().size());

    g.removeEdge(e2);
    g.addEdge(V2, V2);
    assertEquals(1, g.edgeSet().size());

    inspector = new ConnectivityInspector<String, DefaultEdge>(g);
    assertEquals(false, inspector.isGraphConnected());
  }