def _calculate_single_discount(self, discount_name, products_quantity,
product_price):
"""Calculates a discount for a single offer
:param discount_name: name of a discount (one of the supported in DCN_TYP_REGEXPS mapping)
:param products_quantity: quantity of products
:param product_price: price of a single product
:return: calculated discount
:rtype: Decimal
:raises ValueError: if a discount_name is not supported (not in DCN_TYP_REGEXPS)
"""
calculated_discount = Decimal("0.00")
for discount_type, regex in self.DCN_TYP_REGEXPS.items():
discount_name_match = re.match(regex, discount_name)
if discount_name_match:
x = int(discount_name_match.group(1))
try:
y = int(discount_name_match.group(2))
except IndexError:
calculated_discount = x_percent_calculator(
x, products_quantity, product_price)
else:
if discount_type == "X_FOR_Y":
calculated_discount = x_for_y_calculator(
x, y, products_quantity, product_price)
elif discount_type == "X_GET_Y":
calculated_discount = x_get_y_calculator(
x, y, products_quantity, product_price)
else:
raise ValueError(
f"Unsupported discount type: {discount_type}")
return calculated_discount
def test_two_for_three_2(self):
with pytest.raises(ValueError):
x_for_y_calculator(2, 3, 2, 1.00)
def test_three_for_one_4(self):
assert x_for_y_calculator(3, 1, 4, 1.22) == Decimal("2.44")
def test_three_for_two_4(self):
assert x_for_y_calculator(3, 2, 4, 1) == Decimal("1.00")
def test_two_for_one_5(self):
assert x_for_y_calculator(2, 1, 5, 1.00) == Decimal("2.00")