@Test(expected = IllegalStateException.class)
public void inconsistentAromaticState() throws Exception {

    SmilesParser smipar = new SmilesParser(SilentChemObjectBuilder.getInstance());
    IAtomContainer mol = smipar.parseSmiles("c1ccccc1");
    for (IAtom atom : mol.atoms())
        atom.setIsAromatic(false);
    SmilesGenerator smigen = new SmilesGenerator(SmiFlavor.UseAromaticSymbols);
    smigen.create(mol);
}