@Test(expected = CDKException.class)
public void aromaticBondTypes() throws Exception {

    IAtomContainer mol = builder.newInstance(IAtomContainer.class);
    mol.addAtom(builder.newInstance(IAtom.class, "C"));
    mol.addAtom(builder.newInstance(IAtom.class, "C"));
    IBond bond = builder.newInstance(IBond.class, mol.getAtom(0), mol.getAtom(1), Order.UNSET);
    bond.setIsAromatic(true);
    mol.addBond(bond);
    StringWriter sw = new StringWriter();
    try (MDLV2000Writer mdlw = new MDLV2000Writer(sw)) {
        mdlw.write(mol);
    }
}