public void Add_Should_Add()
        {
            // Arrange
            var request = new CalculateRequest
            {
                FirstNumber  = 1,
                SecondNumber = 2,
                Type         = CalculateType.Add
            };

            // Act
            var sut    = new MathService();
            var result = sut.Calculate(request);

            // Assert
            Assert.Equal(3, result.Result);
        }