public void AsSystemType_ShouldReturnProvidedTaxRate()
        {
            //Arrange
            TaxRate subject = new TestTaxRate(true, 0.01234);

            //Act
            double actual = subject;

            //Assert
            actual.Should().Be(0.01234d);
        }
        public void AsSystemType_ShouldReturnZeroForNonTaxable()
        {
            //Arrange
            TaxRate subject = new TestTaxRate(false, double.MaxValue);

            //Act
            double actual = subject;

            //Assert
            actual.Should().Be(0.0d);
        }