@Test
public void testPyridine() throws Exception {

    IAtomContainer mol = new AtomContainer();
    mol.addAtom(new Atom("N"));
    mol.addAtom(new Atom("C"));
    mol.addBond(0, 1, IBond.Order.SINGLE);
    mol.addAtom(new Atom("C"));
    mol.addBond(1, 2, IBond.Order.DOUBLE);
    mol.addAtom(new Atom("C"));
    mol.addBond(2, 3, IBond.Order.SINGLE);
    mol.addAtom(new Atom("C"));
    mol.addBond(3, 4, IBond.Order.DOUBLE);
    mol.addAtom(new Atom("C"));
    mol.addBond(4, 5, IBond.Order.SINGLE);
    mol.addBond(0, 5, IBond.Order.DOUBLE);
    AtomContainerManipulator.percieveAtomTypesAndConfigureAtoms(mol);
    Assert.assertTrue("Expected the molecule to be aromatic.",
            DoubleBondAcceptingAromaticityDetector.detectAromaticity(mol));
    Iterator<IAtom> atoms = mol.atoms().iterator();
    while (atoms.hasNext()) {
        Assert.assertTrue(atoms.next().getFlag(CDKConstants.ISAROMATIC));
    }
    IRingSet ringset = (new SSSRFinder(mol)).findSSSR();
    int numberOfAromaticRings = 0;
    RingSetManipulator.markAromaticRings(ringset);
    for (int i = 0; i < ringset.getAtomContainerCount(); i++) {
        if (ringset.getAtomContainer(i).getFlag(CDKConstants.ISAROMATIC)) numberOfAromaticRings++;
    }
    Assert.assertEquals(1, numberOfAromaticRings);
}