@Test
public void testReturnsNaNForNonHydrogen() throws Exception {

    IAtomContainer mol = new AtomContainer();
    IAtom atom = new Atom("O");
    mol.addAtom(atom);
    DescriptorValue dv = descriptor.calculate(atom, mol);
    IDescriptorResult result = dv.getValue();
    Assert.assertNotNull(result);
    Assert.assertTrue(result instanceof DoubleArrayResult);
    DoubleArrayResult dResult = (DoubleArrayResult) result;
    for (int i = 0; i < result.length(); i++) {
        Assert.assertEquals(Double.NaN, dResult.get(i), 0.000001);
    }
}