public void FailWhenGivenANegativeInteger()
        {
            var function = new FactorialFunction();

            var inputs = function.GetInputs();

            Assert.Throws <ArgumentException>(() =>
            {
                inputs[0].Value = -5;
            });
        }
        public void SuccessfullyReturnValueGivenAPositiveDouble()
        {
            var function = new FactorialFunction();

            var inputs = function.GetInputs();

            inputs[0].Value = 5.5;

            var result = function.Calculate(inputs);

            Assert.NotNull(result);
            Assert.Collection(result,
                              i =>
            {
                Assert.Equal(typeof(double), i.Value.GetType());
                Assert.Equal(287.88527781504507, TypeConverter.ToObject <double>(i.Value));
            });
        }
        public void SuccessfullyReturnValueGivenAPositiveInteger()
        {
            var function = new FactorialFunction();

            var inputs = function.GetInputs();

            Assert.Single(inputs);

            inputs[0].Value = 5;

            var result = function.Calculate(inputs);

            Assert.NotNull(result);
            Assert.Collection(result,
                              i =>
            {
                Assert.Equal(typeof(double), i.Value.GetType());
                Assert.Equal(120, TypeConverter.ToObject <int>(i.Value));
            });
        }