public void Carbon13Test()
{
IElementProvider provider = new MockElementProvider();
IElement c = provider.GetElement("C");
IElement c13 = provider.GetElement("C", 13);
var formula = new ChemicalFormula(new[]
{
new EntityCardinality <IElement>(c, 1),
new EntityCardinality <IElement>(c13, 1),
});
var elements = formula.GetElements();
Assert.AreEqual(2, elements.Count);
// Check masses
Assert.AreEqual(c.Isotopes.FirstWithMax(x => x.RelativeAbundance).AtomicMass
+ c13.Isotopes.FirstWithMax(x => x.RelativeAbundance).AtomicMass,
formula.GetMass(MassType.Monoisotopic));
Assert.AreEqual(c.Isotopes.Sum(x => x.AtomicMass * x.RelativeAbundance)
+ c13.Isotopes.Sum(x => x.AtomicMass * x.RelativeAbundance),
formula.GetMass(MassType.Average));
Assert.AreEqual(c13.GetMass(MassType.Monoisotopic), c13.GetMass(MassType.Average));
}