public void SubtractTest()
        {
            // Arrange
            SimpleCalculator sc = new SimpleCalculator();
            // Act
            decimal subtracted = sc.CalculateTwoDecimals("subtract", 3, 2);

            // Assert
            Assert.AreEqual(1, subtracted);
        }
        public void MultiplyTest()
        {
            // Arrange
            SimpleCalculator sc = new SimpleCalculator();
            // Act
            decimal multiplied = sc.CalculateTwoDecimals("multiply", 3, 2);

            // Assert
            Assert.AreEqual(6, multiplied);
        }
        public void AddTest()
        {
            // Arrange
            SimpleCalculator sc = new SimpleCalculator();
            // Act
            decimal added = sc.CalculateTwoDecimals("add", 3, 2);

            // Assert
            Assert.AreEqual(5, added);
        }