public void AddZeroElementToFormula()
{
ChemicalFormula formulaA = new ChemicalFormula("C2H3NO");
ChemicalFormula formulaB = new ChemicalFormula("C2H3NO");
Element n = PeriodicTable.GetElement("N");
formulaA.Add(n, 0);
Assert.AreEqual(formulaA, formulaB);
}