@Test
public void testDefaultValidTrue() throws Exception {

    IRule rule = new MMElementRule();
    IMolecularFormula formula = new MolecularFormula();
    formula.addIsotope(builder.newInstance(IIsotope.class, "C"), 2);
    formula.addIsotope(builder.newInstance(IIsotope.class, "H"), 6);
    Assert.assertEquals(1.0, rule.validate(formula), 0.0001);
}