/** HG: measures time needed to check a pair of huge random graphs */
  @Test
  public void testHugeGraph() {
    int n = 700;
    long time = System.currentTimeMillis();

    DirectedGraph<Integer, DefaultEdge>
        g1 = SubgraphIsomorphismTestUtils.randomGraph(n, n * n / 50, 12345),
        g2 = SubgraphIsomorphismTestUtils.randomSubgraph(g1, n / 2, 54321);

    VF2SubgraphIsomorphismInspector<Integer, DefaultEdge> vf2 =
        new VF2SubgraphIsomorphismInspector<>(g1, g2);

    assertEquals(true, vf2.isomorphismExists());

    SubgraphIsomorphismTestUtils.showLog(
        "|V1| = "
            + g1.vertexSet().size()
            + ", |E1| = "
            + g1.edgeSet().size()
            + ", |V2| = "
            + g2.vertexSet().size()
            + ", |E2| = "
            + g2.edgeSet().size()
            + " - "
            + (System.currentTimeMillis() - time)
            + "ms");
  }
  /** RG-1: Tests if a all matchings are correct (on some random graphs). */
  @Test
  public void testRandomGraphs() {
    Random rnd = new Random();
    rnd.setSeed(54321);

    for (int i = 1; i < 50; i++) {
      int vertexCount = 2 + rnd.nextInt(i),
          edgeCount = vertexCount + rnd.nextInt(vertexCount * (vertexCount - 1)) / 2,
          subVertexCount = 1 + rnd.nextInt(vertexCount);

      DirectedGraph<Integer, DefaultEdge>
          g1 = SubgraphIsomorphismTestUtils.randomGraph(vertexCount, edgeCount, i),
          g2 = SubgraphIsomorphismTestUtils.randomSubgraph(g1, subVertexCount, i);

      VF2SubgraphIsomorphismInspector<Integer, DefaultEdge> vf2 =
          new VF2SubgraphIsomorphismInspector<>(g1, g2);

      SubgraphIsomorphismTestUtils.showLog(i + ": " + vertexCount + "v, " + edgeCount + "e ");

      for (Iterator<GraphMapping<Integer, DefaultEdge>> mappings = vf2.getMappings();
          mappings.hasNext(); ) {
        assertEquals(true, SubgraphIsomorphismTestUtils.isCorrectMatching(mappings.next(), g1, g2));
        SubgraphIsomorphismTestUtils.showLog(".");
      }
      SubgraphIsomorphismTestUtils.showLog("\n");
    }
  }