Python-Design-Patterns proxy
proxy Model
Python-Design-Patterns proxy
# file: 'proxy.py'
#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
*TL;DR80
Provides an interface to resource that is expensive to duplicate.
"""
from __future__ import print_function
import time
class SalesManager:
def talk(self):
print("Sales Manager ready to talk")
class Proxy:
def __init__(self):
self.busy = 'No'
self.sales = None
def talk(self):
print("Proxy checking for Sales Manager availability")
if self.busy == 'No':
self.sales = SalesManager()
time.sleep(0.1)
self.sales.talk()
else:
time.sleep(0.1)
print("Sales Manager is busy")
class NoTalkProxy(Proxy):
def talk(self):
print("Proxy checking for Sales Manager availability")
time.sleep(0.1)
print("This Sales Manager will not talk to you", "whether he/she is busy or not")
if __name__ == '__main__':
p = Proxy()
p.talk()
p.busy = 'Yes'
p.talk()
p = NoTalkProxy()
p.talk()
p.busy = 'Yes'
p.talk()
### OUTPUT ###
# Proxy checking for Sales Manager availability
# Sales Manager ready to talk
# Proxy checking for Sales Manager availability
# Sales Manager is busy
# Proxy checking for Sales Manager availability
# This Sales Manager will not talk to you whether he/she is busy or not
# Proxy checking for Sales Manager availability
# This Sales Manager will not talk to you whether he/she is busy or not
proxy.py
proxy Test
# file: 'test_proxy.py'
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import sys
from time import time
import unittest
from structural.proxy import Proxy, NoTalkProxy
if sys.version_info[0] == 2:
from StringIO import StringIO
else:
from io import StringIO
class ProxyTest(unittest.TestCase):
@classmethod
def setUpClass(cls):
""" Class scope setup. """
cls.p = Proxy()
def setUp(cls):
""" Function/test case scope setup. """
cls.output = StringIO()
cls.saved_stdout = sys.stdout
sys.stdout = cls.output
def tearDown(cls):
""" Function/test case scope teardown. """
cls.output.close()
sys.stdout = cls.saved_stdout
def test_sales_manager_shall_talk_through_proxy_with_delay(cls):
cls.p.busy = 'No'
start_time = time()
cls.p.talk()
end_time = time()
execution_time = end_time - start_time
print_output = cls.output.getvalue()
expected_print_output = 'Proxy checking for Sales Manager availability\n\
Sales Manager ready to talk\n'
cls.assertEqual(print_output, expected_print_output)
expected_execution_time = 1
cls.assertEqual(int(execution_time * 10), expected_execution_time)
def test_sales_manager_shall_respond_through_proxy_with_delay(cls):
cls.p.busy = 'Yes'
start_time = time()
cls.p.talk()
end_time = time()
execution_time = end_time - start_time
print_output = cls.output.getvalue()
expected_print_output = 'Proxy checking for Sales Manager availability\n\
Sales Manager is busy\n'
cls.assertEqual(print_output, expected_print_output)
expected_execution_time = 1
cls.assertEqual(int(execution_time * 10), expected_execution_time)
class NoTalkProxyTest(unittest.TestCase):
@classmethod
def setUpClass(cls):
""" Class scope setup. """
cls.ntp = NoTalkProxy()
def setUp(cls):
""" Function/test case scope setup. """
cls.output = StringIO()
cls.saved_stdout = sys.stdout
sys.stdout = cls.output
def tearDown(cls):
""" Function/test case scope teardown. """
cls.output.close()
sys.stdout = cls.saved_stdout
def test_sales_manager_shall_not_talk_through_proxy_with_delay(cls):
cls.ntp.busy = 'No'
start_time = time()
cls.ntp.talk()
end_time = time()
execution_time = end_time - start_time
print_output = cls.output.getvalue()
expected_print_output = 'Proxy checking for Sales Manager availability\n\
This Sales Manager will not talk to you whether he/she is busy or not\n'
cls.assertEqual(print_output, expected_print_output)
expected_execution_time = 1
cls.assertEqual(int(execution_time * 10), expected_execution_time)
def test_sales_manager_shall_not_respond_through_proxy_with_delay(cls):
cls.ntp.busy = 'Yes'
start_time = time()
cls.ntp.talk()
end_time = time()
execution_time = end_time - start_time
print_output = cls.output.getvalue()
expected_print_output = 'Proxy checking for Sales Manager availability\n\
This Sales Manager will not talk to you whether he/she is busy or not\n'
cls.assertEqual(print_output, expected_print_output)
expected_execution_time = 1
cls.assertEqual(int(execution_time * 10), expected_execution_time)
test_proxy.py
