debian-cached-property/tests/test_cached_property_ttl.py

274 lines
7.1 KiB
Python

# -*- coding: utf-8 -*-
"""
test_threaded_cache_property.py
----------------------------------
Tests for `cached-property` module, cached_property_with_ttl.
Tests for `cached-property` module, threaded_cache_property_with_ttl.
"""
import unittest
from freezegun import freeze_time
from cached_property import (
cached_property_with_ttl,
threaded_cached_property_with_ttl
)
from time import sleep
from threading import Lock, Thread
import unittest
from freezegun import freeze_time
from cached_property import cached_property
class TestCachedProperty(unittest.TestCase):
def test_cached_property(self):
class Check(object):
def __init__(self):
self.total1 = 0
self.total2 = 0
@property
def add_control(self):
self.total1 += 1
return self.total1
@cached_property_with_ttl
def add_cached(self):
self.total2 += 1
return self.total2
c = Check()
# The control shows that we can continue to add 1.
self.assertEqual(c.add_control, 1)
self.assertEqual(c.add_control, 2)
# The cached version demonstrates how nothing new is added
self.assertEqual(c.add_cached, 1)
self.assertEqual(c.add_cached, 1)
# Cannot expire the cache.
with freeze_time("9999-01-01"):
self.assertEqual(c.add_cached, 1)
# It's customary for descriptors to return themselves if accessed
# though the class, rather than through an instance.
self.assertTrue(isinstance(Check.add_cached, cached_property_with_ttl))
def test_reset_cached_property(self):
class Check(object):
def __init__(self):
self.total = 0
@cached_property_with_ttl
def add_cached(self):
self.total += 1
return self.total
c = Check()
# Run standard cache assertion
self.assertEqual(c.add_cached, 1)
self.assertEqual(c.add_cached, 1)
# Reset the cache.
del c._cache['add_cached']
self.assertEqual(c.add_cached, 2)
self.assertEqual(c.add_cached, 2)
def test_none_cached_property(self):
class Check(object):
def __init__(self):
self.total = None
@cached_property_with_ttl
def add_cached(self):
return self.total
c = Check()
# Run standard cache assertion
self.assertEqual(c.add_cached, None)
class TestThreadingIssues(unittest.TestCase):
def test_threads(self):
""" How well does the standard cached_property implementation work with threads?
Short answer: It doesn't! Use threaded_cached_property instead!
""" # noqa
class Check(object):
def __init__(self):
self.total = 0
self.lock = Lock()
@cached_property_with_ttl
def add_cached(self):
sleep(1)
# Need to guard this since += isn't atomic.
with self.lock:
self.total += 1
return self.total
c = Check()
threads = []
num_threads = 10
for x in range(num_threads):
thread = Thread(target=lambda: c.add_cached)
thread.start()
threads.append(thread)
for thread in threads:
thread.join()
# Threads means that caching is bypassed.
self.assertNotEqual(c.add_cached, 1)
# This assertion hinges on the fact the system executing the test can
# spawn and start running num_threads threads within the sleep period
# (defined in the Check class as 1 second). If num_threads were to be
# massively increased (try 10000), the actual value returned would be
# between 1 and num_threads, depending on thread scheduling and
# preemption.
self.assertEqual(c.add_cached, num_threads)
class TestCachedPropertyWithTTL(unittest.TestCase):
def test_ttl_expiry(self):
class Check(object):
def __init__(self):
self.total = 0
@cached_property_with_ttl(ttl=100000)
def add_cached(self):
self.total += 1
return self.total
c = Check()
# Run standard cache assertion
self.assertEqual(c.add_cached, 1)
self.assertEqual(c.add_cached, 1)
# Expire the cache.
with freeze_time("9999-01-01"):
self.assertEqual(c.add_cached, 2)
self.assertEqual(c.add_cached, 2)
class TestCachedProperty(unittest.TestCase):
def test_cached_property(self):
class Check(object):
def __init__(self):
self.total1 = 0
self.total2 = 0
@property
def add_control(self):
self.total1 += 1
return self.total1
@threaded_cached_property_with_ttl
def add_cached(self):
self.total2 += 1
return self.total2
c = Check()
# The control shows that we can continue to add 1.
self.assertEqual(c.add_control, 1)
self.assertEqual(c.add_control, 2)
# The cached version demonstrates how nothing new is added
self.assertEqual(c.add_cached, 1)
self.assertEqual(c.add_cached, 1)
def test_reset_cached_property(self):
class Check(object):
def __init__(self):
self.total = 0
@threaded_cached_property_with_ttl
def add_cached(self):
self.total += 1
return self.total
c = Check()
# Run standard cache assertion
self.assertEqual(c.add_cached, 1)
self.assertEqual(c.add_cached, 1)
# Reset the cache.
del c._cache['add_cached']
self.assertEqual(c.add_cached, 2)
self.assertEqual(c.add_cached, 2)
def test_none_cached_property(self):
class Check(object):
def __init__(self):
self.total = None
@threaded_cached_property_with_ttl
def add_cached(self):
return self.total
c = Check()
# Run standard cache assertion
self.assertEqual(c.add_cached, None)
class TestThreadingIssues(unittest.TestCase):
def test_threads(self):
""" How well does this implementation work with threads?"""
class Check(object):
def __init__(self):
self.total = 0
self.lock = Lock()
@threaded_cached_property_with_ttl
def add_cached(self):
sleep(1)
# Need to guard this since += isn't atomic.
with self.lock:
self.total += 1
return self.total
c = Check()
threads = []
for x in range(10):
thread = Thread(target=lambda: c.add_cached)
thread.start()
threads.append(thread)
for thread in threads:
thread.join()
self.assertEqual(c.add_cached, 1)