@Test
public void testGetString__String_IMolecularFormula() {

    Assert.assertNotNull(MolecularFormulaManipulator.getMolecularFormula("C10H16", new MolecularFormula()));
    Assert.assertNotNull(MolecularFormulaManipulator.getMolecularFormula("C10H16", builder));
    IMolecularFormula formula = MolecularFormulaManipulator.getMolecularFormula("O3(Fe(O2))3", builder);
    Assert.assertEquals( formula.getIsotopeCount( new Atom("Fe") ), 3);
    Assert.assertEquals( formula.getIsotopeCount( new Atom("O") ), 9);
}