@Test
public void testDistanceToAtomDescriptor() throws ClassNotFoundException, CDKException, java.lang.Exception {

    IAtomicDescriptor descriptor = new DistanceToAtomDescriptor();
    Object[] params = {Integer.valueOf(2)};
    descriptor.setParameters(params);
    IAtomContainer mol = new AtomContainer();
    Atom a0 = new Atom("C");
    mol.addAtom(a0);
    a0.setPoint3d(new Point3d(1.2492, -0.2810, 0.0000));
    Atom a1 = new Atom("C");
    mol.addAtom(a1);
    a1.setPoint3d(new Point3d(0.0000, 0.6024, -0.0000));
    Atom a2 = new Atom("C");
    mol.addAtom(a2);
    a2.setPoint3d(new Point3d(-1.2492, -0.2810, 0.0000));
    mol.addBond(0, 1, IBond.Order.SINGLE); // 1
    mol.addBond(1, 2, IBond.Order.SINGLE); // 2
    // mol.addBond(2, 3, IBond.Order.SINGLE); // 3 // jwmay: there is no atom at index 3
    Assert.assertEquals(2.46, ((DoubleResult) descriptor.calculate(mol.getAtom(0), mol).getValue()).doubleValue(),
            0.1);
}