public void Given_NonExistentProductName_Then_GetPoductByNameWillReturnNull()
        {
            Data.Product expected = null;
            Data.Product actual   = sut.GetPoductByName("Book");

            actual.Should().Be(expected);
        }
        public void Given_ValidPosition_Then_GetProductByPositionReturnsProduct()
        {
            Data.Product actual   = sut.GetProductByPosition(2);
            Data.Product expected = products.ElementAt(2);

            actual.Should().Be(expected);
        }
        public void Given_ExistingProductName_Then_GetPoductByNameWillReturnProduct()
        {
            string existingProductName = "Rice";

            Data.Product expected = products.ElementAt(0);
            Data.Product actual   = sut.GetPoductByName(existingProductName);

            actual.Should().Be(expected);
        }