public static void Multiply()
{
ChemicalFormula formulaA = ChemicalFormula.ParseFormula("C2H3NO");
formulaA.Multiply(2);
ChemicalFormula formulaB = ChemicalFormula.ParseFormula("C4H6N2O2");
Assert.AreEqual(formulaA, formulaB);
Assert.IsFalse(formulaA.Equals(null));
}