@Test
public void testGetIsotopes_IMolecularFormula_Charged() {

    IsotopePatternGenerator isogen = new IsotopePatternGenerator(.1);
    
    IMolecularFormula mfPositive = MolecularFormulaManipulator.getMolecularFormula("C6H11O6Na", builder);
    mfPositive.setCharge(1);
    IsotopePattern ip1 = isogen.getIsotopes(mfPositive);
    Assert.assertEquals(1, ip1.getNumberOfIsotopes());
    isogen = new IsotopePatternGenerator(.1);
    IMolecularFormula mfNeutral = MolecularFormulaManipulator.getMolecularFormula("C6H12O6Na", builder);
    mfNeutral.setCharge(0);
    IsotopePattern ip2 = isogen.getIsotopes(mfNeutral);
    Assert.assertEquals(1, ip2.getNumberOfIsotopes());
    Assert.assertNotEquals(ip1.getIsotope(0).getMass(), ip2.getIsotope(0).getMass());
}