@Test
public void testDefaultValidFalse() throws ClassNotFoundException, CDKException, Exception {

    IRule rule = new RDBERule();
    IMolecularFormula formula = MolecularFormulaManipulator.getMajorIsotopeMolecularFormula("C2H4", builder);
    Assert.assertEquals(1.0, rule.validate(formula), 0.0001);
}