242 lines
7.7 KiB
Python
242 lines
7.7 KiB
Python
# -*- coding: utf-8 -*-
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import time
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import unittest
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from threading import Lock, Thread
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from freezegun import freeze_time
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import cached_property
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def CheckFactory(cached_property_decorator, threadsafe=False):
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"""
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Create dynamically a Check class whose add_cached method is decorated by
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the cached_property_decorator.
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"""
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class Check(object):
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def __init__(self):
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self.control_total = 0
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self.cached_total = 0
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self.lock = Lock()
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@property
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def add_control(self):
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self.control_total += 1
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return self.control_total
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@cached_property_decorator
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def add_cached(self):
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if threadsafe:
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time.sleep(1)
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# Need to guard this since += isn't atomic.
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with self.lock:
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self.cached_total += 1
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else:
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self.cached_total += 1
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return self.cached_total
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def run_threads(self, num_threads):
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threads = []
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for _ in range(num_threads):
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thread = Thread(target=lambda: self.add_cached)
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thread.start()
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threads.append(thread)
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for thread in threads:
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thread.join()
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return Check
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class TestCachedProperty(unittest.TestCase):
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"""Tests for cached_property"""
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cached_property_factory = cached_property.cached_property
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def assert_control(self, check, expected):
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"""
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Assert that both `add_control` and 'control_total` equal `expected`
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"""
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self.assertEqual(check.add_control, expected)
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self.assertEqual(check.control_total, expected)
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def assert_cached(self, check, expected):
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"""
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Assert that both `add_cached` and 'cached_total` equal `expected`
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"""
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self.assertEqual(check.add_cached, expected)
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self.assertEqual(check.cached_total, expected)
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def test_cached_property(self):
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Check = CheckFactory(self.cached_property_factory)
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check = Check()
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# The control shows that we can continue to add 1
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self.assert_control(check, 1)
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self.assert_control(check, 2)
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# The cached version demonstrates how nothing is added after the first
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self.assert_cached(check, 1)
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self.assert_cached(check, 1)
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# The cache does not expire
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with freeze_time("9999-01-01"):
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self.assert_cached(check, 1)
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# Typically descriptors return themselves if accessed though the class
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# rather than through an instance.
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self.assertTrue(isinstance(Check.add_cached,
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self.cached_property_factory))
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def test_reset_cached_property(self):
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Check = CheckFactory(self.cached_property_factory)
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check = Check()
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# Run standard cache assertion
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self.assert_cached(check, 1)
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self.assert_cached(check, 1)
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# Clear the cache
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del check.add_cached
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# Value is cached again after the next access
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self.assert_cached(check, 2)
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self.assert_cached(check, 2)
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def test_none_cached_property(self):
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class Check(object):
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def __init__(self):
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self.cached_total = None
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@self.cached_property_factory
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def add_cached(self):
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return self.cached_total
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self.assert_cached(Check(), None)
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def test_set_cached_property(self):
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Check = CheckFactory(self.cached_property_factory)
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check = Check()
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check.add_cached = 'foo'
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self.assertEqual(check.add_cached, 'foo')
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self.assertEqual(check.cached_total, 0)
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def test_threads(self):
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Check = CheckFactory(self.cached_property_factory, threadsafe=True)
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check = Check()
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num_threads = 5
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# cached_property_with_ttl is *not* thread-safe!
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check.run_threads(num_threads)
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# This assertion hinges on the fact the system executing the test can
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# spawn and start running num_threads threads within the sleep period
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# (defined in the Check class as 1 second). If num_threads were to be
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# massively increased (try 10000), the actual value returned would be
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# between 1 and num_threads, depending on thread scheduling and
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# preemption.
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self.assert_cached(check, num_threads)
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self.assert_cached(check, num_threads)
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# The cache does not expire
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with freeze_time("9999-01-01"):
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check.run_threads(num_threads)
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self.assert_cached(check, num_threads)
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self.assert_cached(check, num_threads)
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class TestThreadedCachedProperty(TestCachedProperty):
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"""Tests for threaded_cached_property"""
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cached_property_factory = cached_property.threaded_cached_property
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def test_threads(self):
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Check = CheckFactory(self.cached_property_factory, threadsafe=True)
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check = Check()
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num_threads = 5
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# threaded_cached_property_with_ttl is thread-safe
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check.run_threads(num_threads)
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self.assert_cached(check, 1)
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self.assert_cached(check, 1)
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# The cache does not expire
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with freeze_time("9999-01-01"):
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check.run_threads(num_threads)
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self.assert_cached(check, 1)
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self.assert_cached(check, 1)
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class TestCachedPropertyWithTTL(TestCachedProperty):
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"""Tests for cached_property_with_ttl"""
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cached_property_factory = cached_property.cached_property_with_ttl
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def test_ttl_expiry(self):
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Check = CheckFactory(self.cached_property_factory(ttl=100000))
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check = Check()
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# Run standard cache assertion
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self.assert_cached(check, 1)
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self.assert_cached(check, 1)
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# The cache expires in the future
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with freeze_time("9999-01-01"):
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self.assert_cached(check, 2)
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self.assert_cached(check, 2)
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# Things are not reverted when we are back to the present
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self.assert_cached(check, 2)
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self.assert_cached(check, 2)
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def test_threads_ttl_expiry(self):
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Check = CheckFactory(self.cached_property_factory(ttl=100000),
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threadsafe=True)
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check = Check()
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num_threads = 5
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# Same as in test_threads
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check.run_threads(num_threads)
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self.assert_cached(check, num_threads)
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self.assert_cached(check, num_threads)
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# The cache expires in the future
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with freeze_time("9999-01-01"):
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check.run_threads(num_threads)
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self.assert_cached(check, 2 * num_threads)
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self.assert_cached(check, 2 * num_threads)
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# Things are not reverted when we are back to the present
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self.assert_cached(check, 2 * num_threads)
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self.assert_cached(check, 2 * num_threads)
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class TestThreadedCachedPropertyWithTTL(TestThreadedCachedProperty,
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TestCachedPropertyWithTTL):
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"""Tests for threaded_cached_property_with_ttl"""
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cached_property_factory = cached_property.threaded_cached_property_with_ttl
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def test_threads_ttl_expiry(self):
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Check = CheckFactory(self.cached_property_factory(ttl=100000),
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threadsafe=True)
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check = Check()
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num_threads = 5
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# Same as in test_threads
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check.run_threads(num_threads)
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self.assert_cached(check, 1)
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self.assert_cached(check, 1)
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# The cache expires in the future
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with freeze_time("9999-01-01"):
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check.run_threads(num_threads)
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self.assert_cached(check, 2)
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self.assert_cached(check, 2)
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# Things are not reverted when we are back to the present
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self.assert_cached(check, 2)
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self.assert_cached(check, 2)
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