@Test
public void testCovalentMetal() throws Exception {

    SmilesParser sp = new SmilesParser(DefaultChemObjectBuilder.getInstance());
    IAtomContainer mol = sp.parseSmiles("CCCC[Sn](CCCC)(CCCC)c1cc(Cl)c(Nc2nc(C)nc(N(CCC)CC3CC3)c2Cl)c(Cl)c1");
    DoubleArrayResult ret = (DoubleArrayResult) descriptor.calculate(mol).getValue();
    Assert.assertNotNull(ret);
}