@Test
public void testGetString_IMolecularFormula() {

    IMolecularFormula mf1 = new MolecularFormula();
    mf1.addIsotope(builder.newInstance(IIsotope.class, "C"), 10);
    mf1.addIsotope(builder.newInstance(IIsotope.class, "H"), 16);
    Assert.assertEquals("C10H16", MolecularFormulaManipulator.getString(mf1));
    IMolecularFormula mf2 = new MolecularFormula();
    mf2.addIsotope(builder.newInstance(IAtom.class, "H"), 16);
    mf2.addIsotope(builder.newInstance(IAtom.class, "C"), 10);
    Assert.assertEquals("C10H16", MolecularFormulaManipulator.getString(mf2));
    Assert.assertEquals(MolecularFormulaManipulator.getString(mf2), MolecularFormulaManipulator.getString(mf1));
}