@Test
public void carbon_anion() {

    IAtomContainer container = new AtomContainer();
    IAtom atom = new Atom("C");
    atom.setFormalCharge(+1);
    container.addAtom(atom);
    MDLValence.apply(container);
    assertThat(atom.getValency(), is(3));
    assertThat(atom.getImplicitHydrogenCount(), is(3));
}