@Test public void azulene() throws Exception {

    Graph g = Graph.fromSmiles("C1CC2CCCCCC2C1");
    Matching m = MaximumMatching.maximal(g);
    assertThat(m.matches(), hasItems(Tuple.of(0, 1),
                                     Tuple.of(2, 3),
                                     Tuple.of(4, 5),
                                     Tuple.of(6, 7),
                                     Tuple.of(8, 9)));
}