public void FactShouldThrowWhenNegativeNumber()
 {
     var func = new Fact();
     var args = FunctionsHelper.CreateArgs(-1);
     func.Execute(args, _parsingContext);
 }
 public void FactShouldRoundDownAndReturnCorrectResult()
 {
     var func = new Fact();
     var args = FunctionsHelper.CreateArgs(5.99);
     var result = func.Execute(args, _parsingContext);
     Assert.AreEqual(120d, result.Result);
 }