@Test
public void testBenzeneWithDoubleBonds() {

    IAtomContainer benzene = builder.newInstance(IAtomContainer.class);
    AbstractSignatureTest.addCarbons(benzene, 6);
    for (int i = 0; i < 6; i++) {
        AbstractSignatureTest.addHydrogens(benzene, i, 1);
    }
    benzene.addBond(0, 1, IBond.Order.SINGLE);
    benzene.addBond(1, 2, IBond.Order.DOUBLE);
    benzene.addBond(2, 3, IBond.Order.SINGLE);
    benzene.addBond(3, 4, IBond.Order.DOUBLE);
    benzene.addBond(4, 5, IBond.Order.SINGLE);
    benzene.addBond(5, 0, IBond.Order.DOUBLE);
    MoleculeSignature signature = new MoleculeSignature(benzene);
    String carbonSignature = signature.signatureStringForVertex(0);
    for (int i = 1; i < 6; i++) {
        String carbonSignatureI = signature.signatureStringForVertex(i);
        Assert.assertEquals(carbonSignature, carbonSignatureI);
    }
}