@Test
public void testIsValid_NOT() {

    IMolecularFormula formula = new MolecularFormula();
    formula.addIsotope(ifac.getMajorIsotope("C"), 1);
    formula.addIsotope(ifac.getMajorIsotope("H"), 100);
    List<IRule> rules = new ArrayList<IRule>();
    rules.add(new MMElementRule());
    MolecularFormulaChecker MFChecker = new MolecularFormulaChecker(rules);
    IMolecularFormula formulaWith = MFChecker.isValid(formula);
    Assert.assertEquals(0.0d,
                        (double)formulaWith.getProperty((new MMElementRule()).getClass()),
                        0.01);
}