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This commit is contained in:
Luciano Ramalho
2021-08-07 00:44:01 -03:00
parent cbd13885fc
commit 01e717b60a
96 changed files with 580 additions and 1021 deletions
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82
10-dp-1class-func/classic_strategy.py
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@@ -6,20 +6,20 @@
>>> joe = Customer('John Doe', 0) # <1>
>>> ann = Customer('Ann Smith', 1100)
>>> cart = [LineItem('banana', 4, .5), # <2>
... LineItem('apple', 10, 1.5),
... LineItem('watermelon', 5, 5.0)]
>>> cart = (LineItem('banana', 4, Decimal('.5')), # <2>
... LineItem('apple', 10, Decimal('1.5')),
... LineItem('watermelon', 5, Decimal(5)))
>>> Order(joe, cart, FidelityPromo()) # <3>
<Order total: 42.00 due: 42.00>
>>> Order(ann, cart, FidelityPromo()) # <4>
<Order total: 42.00 due: 39.90>
>>> banana_cart = [LineItem('banana', 30, .5), # <5>
... LineItem('apple', 10, 1.5)]
>>> banana_cart = (LineItem('banana', 30, Decimal('.5')), # <5>
... LineItem('apple', 10, Decimal('1.5')))
>>> Order(joe, banana_cart, BulkItemPromo()) # <6>
<Order total: 30.00 due: 28.50>
>>> big_cart = [LineItem(str(item_code), 1, 1.0) # <7>
... for item_code in range(10)]
>>> Order(joe, big_cart, LargeOrderPromo()) # <8>
>>> long_cart = tuple(LineItem(str(sku), 1, Decimal(1)) # <7>
... for sku in range(10))
>>> Order(joe, long_cart, LargeOrderPromo()) # <8>
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, LargeOrderPromo())
<Order total: 42.00 due: 42.00>
@@ -29,44 +29,37 @@
# tag::CLASSIC_STRATEGY[]
from abc import ABC, abstractmethod
import typing
from typing import Sequence, Optional
from collections.abc import Sequence
from decimal import Decimal
from typing import NamedTuple, Optional
class Customer(typing.NamedTuple):
class Customer(NamedTuple):
name: str
fidelity: int
class LineItem:
def __init__(self, product: str, quantity: int, price: float):
self.product = product
self.quantity = quantity
self.price = price
class LineItem(NamedTuple):
product: str
quantity: int
price: Decimal
def total(self):
def total(self) -> Decimal:
return self.price * self.quantity
class Order: # the Context
def __init__(
self,
customer: Customer,
cart: Sequence[LineItem],
promotion: Optional['Promotion'] = None,
):
self.customer = customer
self.cart = list(cart)
self.promotion = promotion
class Order(NamedTuple): # the Context
customer: Customer
cart: Sequence[LineItem]
promotion: Optional['Promotion'] = None
def total(self) -> float:
if not hasattr(self, '__total'):
self.__total = sum(item.total() for item in self.cart)
return self.__total
def total(self) -> Decimal:
totals = (item.total() for item in self.cart)
return sum(totals, start=Decimal(0))
def due(self) -> float:
def due(self) -> Decimal:
if self.promotion is None:
discount = 0.0
discount = Decimal(0)
else:
discount = self.promotion.discount(self)
return self.total() - discount
@@ -77,36 +70,37 @@ class Order: # the Context
class Promotion(ABC): # the Strategy: an abstract base class
@abstractmethod
def discount(self, order: Order) -> float:
def discount(self, order: Order) -> Decimal:
"""Return discount as a positive dollar amount"""
class FidelityPromo(Promotion): # first Concrete Strategy
"""5% discount for customers with 1000 or more fidelity points"""
def discount(self, order: Order) -> float:
return order.total() * 0.05 if order.customer.fidelity >= 1000 else 0
def discount(self, order: Order) -> Decimal:
rate = Decimal('0.05')
if order.customer.fidelity >= 1000:
return order.total() * rate
return Decimal(0)
class BulkItemPromo(Promotion): # second Concrete Strategy
"""10% discount for each LineItem with 20 or more units"""
def discount(self, order: Order) -> float:
discount = 0
def discount(self, order: Order) -> Decimal:
discount = Decimal(0)
for item in order.cart:
if item.quantity >= 20:
discount += item.total() * 0.1
discount += item.total() * Decimal('0.1')
return discount
class LargeOrderPromo(Promotion): # third Concrete Strategy
"""7% discount for orders with 10 or more distinct items"""
def discount(self, order: Order) -> float:
def discount(self, order: Order) -> Decimal:
distinct_items = {item.product for item in order.cart}
if len(distinct_items) >= 10:
return order.total() * 0.07
return 0
return order.total() * Decimal('0.07')
return Decimal(0)
# end::CLASSIC_STRATEGY[]

44
10-dp-1class-func/classic_strategy_test.py
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@@ -1,4 +1,4 @@
from typing import List
from decimal import Decimal
import pytest # type: ignore
@@ -17,47 +17,49 @@ def customer_fidelity_1100() -> Customer:
@pytest.fixture
def cart_plain() -> List[LineItem]:
return [
LineItem('banana', 4, 0.5),
LineItem('apple', 10, 1.5),
LineItem('watermelon', 5, 5.0),
]
def cart_plain() -> tuple[LineItem, ...]:
return (
LineItem('banana', 4, Decimal('0.5')),
LineItem('apple', 10, Decimal('1.5')),
LineItem('watermelon', 5, Decimal('5.0')),
)
def test_fidelity_promo_no_discount(customer_fidelity_0, cart_plain) -> None:
order = Order(customer_fidelity_0, cart_plain, FidelityPromo())
assert order.total() == 42.0
assert order.due() == 42.0
assert order.total() == 42
assert order.due() == 42
def test_fidelity_promo_with_discount(customer_fidelity_1100, cart_plain) -> None:
order = Order(customer_fidelity_1100, cart_plain, FidelityPromo())
assert order.total() == 42.0
assert order.due() == 39.9
assert order.total() == 42
assert order.due() == Decimal('39.9')
def test_bulk_item_promo_no_discount(customer_fidelity_0, cart_plain) -> None:
order = Order(customer_fidelity_0, cart_plain, BulkItemPromo())
assert order.total() == 42.0
assert order.due() == 42.0
assert order.total() == 42
assert order.due() == 42
def test_bulk_item_promo_with_discount(customer_fidelity_0) -> None:
cart = [LineItem('banana', 30, 0.5), LineItem('apple', 10, 1.5)]
cart = [LineItem('banana', 30, Decimal('0.5')),
LineItem('apple', 10, Decimal('1.5'))]
order = Order(customer_fidelity_0, cart, BulkItemPromo())
assert order.total() == 30.0
assert order.due() == 28.5
assert order.total() == 30
assert order.due() == Decimal('28.5')
def test_large_order_promo_no_discount(customer_fidelity_0, cart_plain) -> None:
order = Order(customer_fidelity_0, cart_plain, LargeOrderPromo())
assert order.total() == 42.0
assert order.due() == 42.0
assert order.total() == 42
assert order.due() == 42
def test_large_order_promo_with_discount(customer_fidelity_0) -> None:
cart = [LineItem(str(item_code), 1, 1.0) for item_code in range(10)]
cart = [LineItem(str(item_code), 1, Decimal(1))
for item_code in range(10)]
order = Order(customer_fidelity_0, cart, LargeOrderPromo())
assert order.total() == 10.0
assert order.due() == 9.3
assert order.total() == 10
assert order.due() == Decimal('9.3')

4
10-dp-1class-func/monkeytype/classic_strategy.py
View File

@@ -17,9 +17,9 @@
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, BulkItemPromo()) # <6>
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0) # <7>
>>> long_cart = [LineItem(str(item_code), 1, 1.0) # <7>
... for item_code in range(10)]
>>> Order(joe, long_order, LargeOrderPromo()) # <8>
>>> Order(joe, long_cart, LargeOrderPromo()) # <8>
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, LargeOrderPromo())
<Order total: 42.00 due: 42.00>

21
10-dp-1class-func/promotions.py
View File

@@ -1,20 +1,25 @@
def fidelity_promo(order):
from decimal import Decimal
from strategy import Order
def fidelity_promo(order: Order) -> Decimal: # <3>
"""5% discount for customers with 1000 or more fidelity points"""
return order.total() * 0.05 if order.customer.fidelity >= 1000 else 0
if order.customer.fidelity >= 1000:
return order.total() * Decimal('0.05')
return Decimal(0)
def bulk_item_promo(order):
def bulk_item_promo(order: Order) -> Decimal:
"""10% discount for each LineItem with 20 or more units"""
discount = 0
discount = Decimal(0)
for item in order.cart:
if item.quantity >= 20:
discount += item.total() * 0.1
discount += item.total() * Decimal('0.1')
return discount
def large_order_promo(order):
def large_order_promo(order: Order) -> Decimal:
"""7% discount for orders with 10 or more distinct items"""
distinct_items = {item.product for item in order.cart}
if len(distinct_items) >= 10:
return order.total() * 0.07
return 0
return order.total() * Decimal('0.07')
return Decimal(0)

4
10-dp-1class-func/pytypes/classic_strategy.py
View File

@@ -17,9 +17,9 @@
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, BulkItemPromo()) # <6>
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0) # <7>
>>> long_cart = [LineItem(str(item_code), 1, 1.0) # <7>
... for item_code in range(10)]
>>> Order(joe, long_order, LargeOrderPromo()) # <8>
>>> Order(joe, long_cart, LargeOrderPromo()) # <8>
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, LargeOrderPromo())
<Order total: 42.00 due: 42.00>

15
10-dp-1class-func/requirements.txt
View File

@@ -1,13 +1,2 @@
mypy==0.770
mypy-extensions==0.4.3
typed-ast==1.4.1
typing-extensions==3.7.4.1
attrs==19.3.0
more-itertools==8.2.0
packaging==20.3
pluggy==0.13.1
py==1.10.0
pyparsing==2.4.6
pytest==5.4.1
six==1.14.0
wcwidth==0.1.9
mypy==0.910
pytest==6.2.4

78
10-dp-1class-func/strategy.py
View File

@@ -6,20 +6,20 @@
>>> joe = Customer('John Doe', 0) # <1>
>>> ann = Customer('Ann Smith', 1100)
>>> cart = [LineItem('banana', 4, .5),
... LineItem('apple', 10, 1.5),
... LineItem('watermelon', 5, 5.0)]
>>> cart = [LineItem('banana', 4, Decimal('.5')),
... LineItem('apple', 10, Decimal('1.5')),
... LineItem('watermelon', 5, Decimal(5))]
>>> Order(joe, cart, fidelity_promo) # <2>
<Order total: 42.00 due: 42.00>
>>> Order(ann, cart, fidelity_promo)
<Order total: 42.00 due: 39.90>
>>> banana_cart = [LineItem('banana', 30, .5),
... LineItem('apple', 10, 1.5)]
>>> banana_cart = [LineItem('banana', 30, Decimal('.5')),
... LineItem('apple', 10, Decimal('1.5'))]
>>> Order(joe, banana_cart, bulk_item_promo) # <3>
<Order total: 30.00 due: 28.50>
>>> big_cart = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, Decimal(1))
... for item_code in range(10)]
>>> Order(joe, big_cart, large_order_promo)
>>> Order(joe, long_cart, large_order_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, large_order_promo)
<Order total: 42.00 due: 42.00>
@@ -28,75 +28,71 @@
"""
# tag::STRATEGY[]
import typing
from typing import Sequence, Optional, Callable
from collections.abc import Sequence
from dataclasses import dataclass
from decimal import Decimal
from typing import Optional, Callable, NamedTuple
class Customer(typing.NamedTuple):
class Customer(NamedTuple):
name: str
fidelity: int
class LineItem:
def __init__(self, product: str, quantity: int, price: float):
self.product = product
self.quantity = quantity
self.price = price
class LineItem(NamedTuple):
product: str
quantity: int
price: Decimal
def total(self):
return self.price * self.quantity
@dataclass(frozen=True)
class Order: # the Context
def __init__(
self,
customer: Customer,
cart: Sequence[LineItem],
promotion: Optional[Callable[['Order'], float]] = None,
) -> None:
self.customer = customer
self.cart = list(cart)
self.promotion = promotion
customer: Customer
cart: Sequence[LineItem]
promotion: Optional[Callable[['Order'], Decimal]] = None # <1>
def total(self) -> float:
if not hasattr(self, '__total'):
self.__total = sum(item.total() for item in self.cart)
return self.__total
def total(self) -> Decimal:
totals = (item.total() for item in self.cart)
return sum(totals, start=Decimal(0))
def due(self) -> float:
def due(self) -> Decimal:
if self.promotion is None:
discount = 0.0
discount = Decimal(0)
else:
discount = self.promotion(self) # <1>
discount = self.promotion(self) # <2>
return self.total() - discount
def __repr__(self):
return f'<Order total: {self.total():.2f} due: {self.due():.2f}>'
# <2>
# <3>
def fidelity_promo(order: Order) -> float: # <3>
def fidelity_promo(order: Order) -> Decimal: # <4>
"""5% discount for customers with 1000 or more fidelity points"""
return order.total() * 0.05 if order.customer.fidelity >= 1000 else 0
if order.customer.fidelity >= 1000:
return order.total() * Decimal('0.05')
return Decimal(0)
def bulk_item_promo(order: Order):
def bulk_item_promo(order: Order) -> Decimal:
"""10% discount for each LineItem with 20 or more units"""
discount = 0
discount = Decimal(0)
for item in order.cart:
if item.quantity >= 20:
discount += item.total() * 0.1
discount += item.total() * Decimal('0.1')
return discount
def large_order_promo(order: Order):
def large_order_promo(order: Order) -> Decimal:
"""7% discount for orders with 10 or more distinct items"""
distinct_items = {item.product for item in order.cart}
if len(distinct_items) >= 10:
return order.total() * 0.07
return 0
return order.total() * Decimal('0.07')
return Decimal(0)
# end::STRATEGY[]

24
10-dp-1class-func/strategy_best.py
View File

@@ -3,19 +3,20 @@
# selecting best promotion from static list of functions
"""
>>> from strategy import Customer, LineItem
>>> joe = Customer('John Doe', 0)
>>> ann = Customer('Ann Smith', 1100)
>>> cart = [LineItem('banana', 4, .5),
... LineItem('apple', 10, 1.5),
... LineItem('watermelon', 5, 5.0)]
>>> banana_cart = [LineItem('banana', 30, .5),
... LineItem('apple', 10, 1.5)]
>>> big_cart = [LineItem(str(item_code), 1, 1.0)
>>> cart = [LineItem('banana', 4, Decimal('.5')),
... LineItem('apple', 10, Decimal('1.5')),
... LineItem('watermelon', 5, Decimal(5))]
>>> banana_cart = [LineItem('banana', 30, Decimal('.5')),
... LineItem('apple', 10, Decimal('1.5'))]
>>> long_cart = [LineItem(str(item_code), 1, Decimal(1))
... for item_code in range(10)]
# tag::STRATEGY_BEST_TESTS[]
>>> Order(joe, big_cart, best_promo) # <1>
>>> Order(joe, long_cart, best_promo) # <1>
<Order total: 10.00 due: 9.30>
>>> Order(joe, banana_cart, best_promo) # <2>
<Order total: 30.00 due: 28.50>
@@ -25,7 +26,9 @@
# end::STRATEGY_BEST_TESTS[]
"""
from strategy import Customer, LineItem, Order
from decimal import Decimal
from strategy import Order
from strategy import fidelity_promo, bulk_item_promo, large_order_promo
# tag::STRATEGY_BEST[]
@@ -33,9 +36,8 @@ from strategy import fidelity_promo, bulk_item_promo, large_order_promo
promos = [fidelity_promo, bulk_item_promo, large_order_promo] # <1>
def best_promo(order) -> float: # <2>
"""Select best discount available
"""
def best_promo(order: Order) -> Decimal: # <2>
"""Compute the best discount available"""
return max(promo(order) for promo in promos) # <3>

99
10-dp-1class-func/strategy_best2.py
View File

@@ -3,29 +3,31 @@
# selecting best promotion from current module globals
"""
>>> from decimal import Decimal
>>> from strategy import Customer, LineItem, Order
>>> joe = Customer('John Doe', 0)
>>> ann = Customer('Ann Smith', 1100)
>>> cart = [LineItem('banana', 4, .5),
... LineItem('apple', 10, 1.5),
... LineItem('watermelon', 5, 5.0)]
>>> cart = [LineItem('banana', 4, Decimal('.5')),
... LineItem('apple', 10, Decimal('1.5')),
... LineItem('watermelon', 5, Decimal(5))]
>>> Order(joe, cart, fidelity_promo)
<Order total: 42.00 due: 42.00>
>>> Order(ann, cart, fidelity_promo)
<Order total: 42.00 due: 39.90>
>>> banana_cart = [LineItem('banana', 30, .5),
... LineItem('apple', 10, 1.5)]
>>> banana_cart = [LineItem('banana', 30, Decimal('.5')),
... LineItem('apple', 10, Decimal('1.5'))]
>>> Order(joe, banana_cart, bulk_item_promo)
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, Decimal(1))
... for item_code in range(10)]
>>> Order(joe, long_order, large_order_promo)
>>> Order(joe, long_cart, large_order_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, large_order_promo)
<Order total: 42.00 due: 42.00>
# tag::STRATEGY_BEST_TESTS[]
>>> Order(joe, long_order, best_promo)
>>> Order(joe, long_cart, best_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, banana_cart, best_promo)
<Order total: 30.00 due: 28.50>
@@ -35,78 +37,21 @@
# end::STRATEGY_BEST_TESTS[]
"""
from collections import namedtuple
Customer = namedtuple('Customer', 'name fidelity')
class LineItem:
def __init__(self, product, quantity, price):
self.product = product
self.quantity = quantity
self.price = price
def total(self):
return self.price * self.quantity
class Order: # the Context
def __init__(self, customer, cart, promotion=None):
self.customer = customer
self.cart = list(cart)
self.promotion = promotion
def total(self):
if not hasattr(self, '__total'):
self.__total = sum(item.total() for item in self.cart)
return self.__total
def due(self):
if self.promotion is None:
discount = 0
else:
discount = self.promotion(self)
return self.total() - discount
def __repr__(self):
return f'<Order total: {self.total():.2f} due: {self.due():.2f}>'
def fidelity_promo(order):
"""5% discount for customers with 1000 or more fidelity points"""
return order.total() * 0.05 if order.customer.fidelity >= 1000 else 0
def bulk_item_promo(order):
"""10% discount for each LineItem with 20 or more units"""
discount = 0
for item in order.cart:
if item.quantity >= 20:
discount += item.total() * 0.1
return discount
def large_order_promo(order):
"""7% discount for orders with 10 or more distinct items"""
distinct_items = {item.product for item in order.cart}
if len(distinct_items) >= 10:
return order.total() * 0.07
return 0
# tag::STRATEGY_BEST2[]
from decimal import Decimal
from strategy import Order
from strategy import (
fidelity_promo, bulk_item_promo, large_order_promo # <1>
)
promos = [
globals()[name]
for name in globals() # <1>
if name.endswith('_promo') and name != 'best_promo' # <2>
] # <3>
promos = [promo for name, promo in globals().items() # <2>
if name.endswith('_promo') and # <3>
name != 'best_promo' # <4>
]
def best_promo(order):
"""Select best discount available
"""
return max(promo(order) for promo in promos) # <4>
def best_promo(order: Order) -> Decimal: # <5>
"""Compute the best discount available"""
return max(promo(order) for promo in promos)
# end::STRATEGY_BEST2[]

73
10-dp-1class-func/strategy_best3.py
View File

@@ -3,30 +3,32 @@
# selecting best promotion from imported module
"""
>>> from decimal import Decimal
>>> from strategy import Customer, LineItem, Order
>>> from promotions import *
>>> joe = Customer('John Doe', 0)
>>> ann = Customer('Ann Smith', 1100)
>>> cart = [LineItem('banana', 4, .5),
... LineItem('apple', 10, 1.5),
... LineItem('watermelon', 5, 5.0)]
>>> cart = [LineItem('banana', 4, Decimal('.5')),
... LineItem('apple', 10, Decimal('1.5')),
... LineItem('watermelon', 5, Decimal(5))]
>>> Order(joe, cart, fidelity_promo)
<Order total: 42.00 due: 42.00>
>>> Order(ann, cart, fidelity_promo)
<Order total: 42.00 due: 39.90>
>>> banana_cart = [LineItem('banana', 30, .5),
... LineItem('apple', 10, 1.5)]
>>> banana_cart = [LineItem('banana', 30, Decimal('.5')),
... LineItem('apple', 10, Decimal('1.5'))]
>>> Order(joe, banana_cart, bulk_item_promo)
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, Decimal(1))
... for item_code in range(10)]
>>> Order(joe, long_order, large_order_promo)
>>> Order(joe, long_cart, large_order_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, large_order_promo)
<Order total: 42.00 due: 42.00>
# tag::STRATEGY_BEST_TESTS[]
>>> Order(joe, long_order, best_promo)
>>> Order(joe, long_cart, best_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, banana_cart, best_promo)
<Order total: 30.00 due: 28.50>
@@ -36,55 +38,20 @@
# end::STRATEGY_BEST_TESTS[]
"""
from collections import namedtuple
import inspect
import promotions
Customer = namedtuple('Customer', 'name fidelity')
class LineItem:
def __init__(self, product, quantity, price):
self.product = product
self.quantity = quantity
self.price = price
def total(self):
return self.price * self.quantity
class Order: # the Context
def __init__(self, customer, cart, promotion=None):
self.customer = customer
self.cart = list(cart)
self.promotion = promotion
def total(self):
if not hasattr(self, '__total'):
self.__total = sum(item.total() for item in self.cart)
return self.__total
def due(self):
if self.promotion is None:
discount = 0
else:
discount = self.promotion(self)
return self.total() - discount
def __repr__(self):
return f'<Order total: {self.total():.2f} due: {self.due():.2f}>'
# tag::STRATEGY_BEST3[]
promos = [func for name, func in inspect.getmembers(promotions, inspect.isfunction)]
from decimal import Decimal
import inspect
from strategy import Order
import promotions
def best_promo(order):
"""Select best discount available
"""
promos = [func for _, func in inspect.getmembers(promotions, inspect.isfunction)]
def best_promo(order: Order) -> Decimal:
"""Compute the best discount available"""
return max(promo(order) for promo in promos)
# end::STRATEGY_BEST3[]

101
10-dp-1class-func/strategy_best4.py
View File

@@ -4,29 +4,32 @@
# registered by a decorator
"""
>>> from decimal import Decimal
>>> from strategy import Customer, LineItem, Order
>>> from promotions import *
>>> joe = Customer('John Doe', 0)
>>> ann = Customer('Ann Smith', 1100)
>>> cart = [LineItem('banana', 4, .5),
... LineItem('apple', 10, 1.5),
... LineItem('watermelon', 5, 5.0)]
>>> Order(joe, cart, fidelity)
>>> cart = [LineItem('banana', 4, Decimal('.5')),
... LineItem('apple', 10, Decimal('1.5')),
... LineItem('watermelon', 5, Decimal(5))]
>>> Order(joe, cart, fidelity_promo)
<Order total: 42.00 due: 42.00>
>>> Order(ann, cart, fidelity)
>>> Order(ann, cart, fidelity_promo)
<Order total: 42.00 due: 39.90>
>>> banana_cart = [LineItem('banana', 30, .5),
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, bulk_item)
>>> banana_cart = [LineItem('banana', 30, Decimal('.5')),
... LineItem('apple', 10, Decimal('1.5'))]
>>> Order(joe, banana_cart, bulk_item_promo)
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, Decimal(1))
... for item_code in range(10)]
>>> Order(joe, long_order, large_order)
>>> Order(joe, long_cart, large_order_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, large_order)
>>> Order(joe, cart, large_order_promo)
<Order total: 42.00 due: 42.00>
# tag::STRATEGY_BEST_TESTS[]
>>> Order(joe, long_order, best_promo)
>>> Order(joe, long_cart, best_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, banana_cart, best_promo)
<Order total: 30.00 due: 28.50>
@@ -36,47 +39,16 @@
# end::STRATEGY_BEST_TESTS[]
"""
from collections import namedtuple
from typing import Callable, List
Customer = namedtuple('Customer', 'name fidelity')
class LineItem:
def __init__(self, product, quantity, price):
self.product = product
self.quantity = quantity
self.price = price
def total(self):
return self.price * self.quantity
class Order: # the Context
def __init__(self, customer, cart, promotion=None):
self.customer = customer
self.cart = list(cart)
self.promotion = promotion
def total(self):
if not hasattr(self, '__total'):
self.__total = sum(item.total() for item in self.cart)
return self.__total
def due(self):
if self.promotion is None:
discount = 0
else:
discount = self.promotion(self)
return self.total() - discount
def __repr__(self):
return f'<Order total: {self.total():.2f} due: {self.due():.2f}>'
from decimal import Decimal
from typing import Callable
from strategy import Order
# tag::STRATEGY_BEST4[]
Promotion = Callable[[Order], float] # <2>
Promotion = Callable[[Order], Decimal]
promos: list[Promotion] = [] # <1>
def promotion(promo: Promotion) -> Promotion: # <2>
@@ -84,38 +56,35 @@ def promotion(promo: Promotion) -> Promotion: # <2>
return promo
promos: List[Promotion] = [] # <1>
def best_promo(order: Order) -> Decimal:
"""Compute the best discount available"""
return max(promo(order) for promo in promos) # <3>
@promotion # <3>
def fidelity(order: Order) -> float:
@promotion # <4>
def fidelity(order: Order) -> Decimal:
"""5% discount for customers with 1000 or more fidelity points"""
return order.total() * 0.05 if order.customer.fidelity >= 1000 else 0
if order.customer.fidelity >= 1000:
return order.total() * Decimal('0.05')
return Decimal(0)
@promotion
def bulk_item(order: Order) -> float:
def bulk_item(order: Order) -> Decimal:
"""10% discount for each LineItem with 20 or more units"""
discount = 0
discount = Decimal(0)
for item in order.cart:
if item.quantity >= 20:
discount += item.total() * 0.1
discount += item.total() * Decimal('0.1')
return discount
@promotion
def large_order(order: Order) -> float:
def large_order(order: Order) -> Decimal:
"""7% discount for orders with 10 or more distinct items"""
distinct_items = {item.product for item in order.cart}
if len(distinct_items) >= 10:
return order.total() * 0.07
return 0
def best_promo(order: Order) -> float: # <4>
"""Select best discount available
"""
return max(promo(order) for promo in promos)
return order.total() * Decimal('0.07')
return Decimal(0)
# end::STRATEGY_BEST4[]

4
10-dp-1class-func/strategy_param.py
View File

@@ -15,9 +15,9 @@
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, bulk_item_promo(10))
<Order total: 30.00 due: 28.50>
>>> big_cart = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, 1.0)
... for item_code in range(10)]
>>> Order(joe, big_cart, LargeOrderPromo(7))
>>> Order(joe, long_cart, LargeOrderPromo(7))
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, LargeOrderPromo(7))
<Order total: 42.00 due: 42.00>

2
10-dp-1class-func/strategy_param_test.py
View File

@@ -47,7 +47,7 @@ def test_large_order_promo_with_discount(customer_fidelity_0) -> None:
assert order.due() == 9.3
def test_general_discount(customer_fidelity_0, cart_plain) -> None:
def test_general_discount(customer_fidelity_1100, cart_plain) -> None:
general_promo: Promotion = functools.partial(general_discount, 5)
order = Order(customer_fidelity_1100, cart_plain, general_promo)
assert order.total() == 42.0

45
10-dp-1class-func/strategy_test.py
View File

@@ -1,4 +1,4 @@
from typing import List
from decimal import Decimal
import pytest # type: ignore
@@ -17,47 +17,50 @@ def customer_fidelity_1100() -> Customer:
@pytest.fixture
def cart_plain() -> List[LineItem]:
return [
LineItem('banana', 4, 0.5),
LineItem('apple', 10, 1.5),
LineItem('watermelon', 5, 5.0),
]
def cart_plain() -> tuple[LineItem, ...]:
return (
LineItem('banana', 4, Decimal('0.5')),
LineItem('apple', 10, Decimal('1.5')),
LineItem('watermelon', 5, Decimal('5.0')),
)
def test_fidelity_promo_no_discount(customer_fidelity_0, cart_plain) -> None:
order = Order(customer_fidelity_0, cart_plain, fidelity_promo)
assert order.total() == 42.0
assert order.due() == 42.0
assert order.total() == 42
assert order.due() == 42
def test_fidelity_promo_with_discount(customer_fidelity_1100, cart_plain) -> None:
order = Order(customer_fidelity_1100, cart_plain, fidelity_promo)
assert order.total() == 42.0
assert order.due() == 39.9
assert order.total() == 42
assert order.due() == Decimal('39.9')
def test_bulk_item_promo_no_discount(customer_fidelity_0, cart_plain) -> None:
order = Order(customer_fidelity_0, cart_plain, bulk_item_promo)
assert order.total() == 42.0
assert order.due() == 42.0
assert order.total() == 42
assert order.due() == 42
def test_bulk_item_promo_with_discount(customer_fidelity_0) -> None:
cart = [LineItem('banana', 30, 0.5), LineItem('apple', 10, 1.5)]
cart = [LineItem('banana', 30, Decimal('0.5')),
LineItem('apple', 10, Decimal('1.5'))]
order = Order(customer_fidelity_0, cart, bulk_item_promo)
assert order.total() == 30.0
assert order.due() == 28.5
assert order.total() == 30
assert order.due() == Decimal('28.5')
def test_large_order_promo_no_discount(customer_fidelity_0, cart_plain) -> None:
order = Order(customer_fidelity_0, cart_plain, large_order_promo)
assert order.total() == 42.0
assert order.due() == 42.0
assert order.total() == 42
assert order.due() == 42
def test_large_order_promo_with_discount(customer_fidelity_0) -> None:
cart = [LineItem(str(item_code), 1, 1.0) for item_code in range(10)]
cart = [LineItem(str(item_code), 1, Decimal(1))
for item_code in range(10)]
order = Order(customer_fidelity_0, cart, large_order_promo)
assert order.total() == 10.0
assert order.due() == 9.3
assert order.total() == 10
assert order.due() == Decimal('9.3')

4
10-dp-1class-func/untyped/classic_strategy.py
View File

@@ -17,9 +17,9 @@
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, BulkItemPromo()) # <6>
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0) # <7>
>>> long_cart = [LineItem(str(item_code), 1, 1.0) # <7>
... for item_code in range(10)]
>>> Order(joe, long_order, LargeOrderPromo()) # <8>
>>> Order(joe, long_cart, LargeOrderPromo()) # <8>
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, LargeOrderPromo())
<Order total: 42.00 due: 42.00>

4
10-dp-1class-func/untyped/strategy.py
View File

@@ -17,9 +17,9 @@
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, bulk_item_promo) # <3>
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, 1.0)
... for item_code in range(10)]
>>> Order(joe, long_order, large_order_promo)
>>> Order(joe, long_cart, large_order_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, large_order_promo)
<Order total: 42.00 due: 42.00>

6
10-dp-1class-func/untyped/strategy_best.py
View File

@@ -16,16 +16,16 @@
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, bulk_item_promo)
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, 1.0)
... for item_code in range(10)]
>>> Order(joe, long_order, large_order_promo)
>>> Order(joe, long_cart, large_order_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, large_order_promo)
<Order total: 42.00 due: 42.00>
# tag::STRATEGY_BEST_TESTS[]
>>> Order(joe, long_order, best_promo) # <1>
>>> Order(joe, long_cart, best_promo) # <1>
<Order total: 10.00 due: 9.30>
>>> Order(joe, banana_cart, best_promo) # <2>
<Order total: 30.00 due: 28.50>

6
10-dp-1class-func/untyped/strategy_best2.py
View File

@@ -16,16 +16,16 @@
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, bulk_item_promo)
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, 1.0)
... for item_code in range(10)]
>>> Order(joe, long_order, large_order_promo)
>>> Order(joe, long_cart, large_order_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, large_order_promo)
<Order total: 42.00 due: 42.00>
# tag::STRATEGY_BEST_TESTS[]
>>> Order(joe, long_order, best_promo)
>>> Order(joe, long_cart, best_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, banana_cart, best_promo)
<Order total: 30.00 due: 28.50>

6
10-dp-1class-func/untyped/strategy_best3.py
View File

@@ -17,16 +17,16 @@
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, bulk_item_promo)
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, 1.0)
... for item_code in range(10)]
>>> Order(joe, long_order, large_order_promo)
>>> Order(joe, long_cart, large_order_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, large_order_promo)
<Order total: 42.00 due: 42.00>
# tag::STRATEGY_BEST_TESTS[]
>>> Order(joe, long_order, best_promo)
>>> Order(joe, long_cart, best_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, banana_cart, best_promo)
<Order total: 30.00 due: 28.50>

6
10-dp-1class-func/untyped/strategy_best4.py
View File

@@ -17,16 +17,16 @@
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, bulk_item)
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, 1.0)
... for item_code in range(10)]
>>> Order(joe, long_order, large_order)
>>> Order(joe, long_cart, large_order)
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, large_order)
<Order total: 42.00 due: 42.00>
# tag::STRATEGY_BEST_TESTS[]
>>> Order(joe, long_order, best_promo)
>>> Order(joe, long_cart, best_promo)
<Order total: 10.00 due: 9.30>
>>> Order(joe, banana_cart, best_promo)
<Order total: 30.00 due: 28.50>

4
10-dp-1class-func/untyped/strategy_param.py
View File

@@ -15,9 +15,9 @@
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, bulk_item_promo(10))
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, 1.0)
... for item_code in range(10)]
>>> Order(joe, long_order, large_order_promo(7))
>>> Order(joe, long_cart, large_order_promo(7))
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, large_order_promo(7))
<Order total: 42.00 due: 42.00>

4
10-dp-1class-func/untyped/strategy_param2.py
View File

@@ -15,9 +15,9 @@
... LineItem('apple', 10, 1.5)]
>>> Order(joe, banana_cart, BulkItemPromo(10))
<Order total: 30.00 due: 28.50>
>>> long_order = [LineItem(str(item_code), 1, 1.0)
>>> long_cart = [LineItem(str(item_code), 1, 1.0)
... for item_code in range(10)]
>>> Order(joe, long_order, LargeOrderPromo(7))
>>> Order(joe, long_cart, LargeOrderPromo(7))
<Order total: 10.00 due: 9.30>
>>> Order(joe, cart, LargeOrderPromo(7))
<Order total: 42.00 due: 42.00>