@Test
public void unlabelledHydrogens() throws Exception {

    IAtomContainer container = new SmilesParser(SilentChemObjectBuilder.getInstance())
            .parseSmiles("[H]C([H])([H])[H]");
    assertThat(InChINumbersTools.getUSmilesNumbers(container), is(new long[]{2, 1, 3, 4, 5}));
}