public void MonomialsAddResultsInException2()
{
IExpressionParser parser = new ExpressionParser();
Monomial monomial = new Monomial(1, "x", 2, parser);
Monomial monomialToAdd = new Monomial(2, "x", 3, parser);
Assert.Throws <InvalidMonomialOperationException>(() =>
monomial.AddMonomialWithSameVariable(monomialToAdd));
}
public void MonomialsAddResultsIn3()
{
IExpressionParser parser = new ExpressionParser();
Monomial monomial = new Monomial(1, "", null, parser);
Monomial monomialToAdd = new Monomial(2, "", null, parser);
Monomial result = monomial.AddMonomialWithSameVariable(monomialToAdd);
Assert.AreEqual("3", result.Expression);
}