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# Copyright (C) 2006, 2008, 2009 Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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"""Tests for the lru_cache module."""
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"""Test helper to walk the LRU list and assert its consistency"""
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node = lru._most_recently_used
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if node.prev is not None:
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raise AssertionError('the _most_recently_used entry is not'
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' supposed to have a previous entry'
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while node is not None:
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if node.next_key is lru_cache._null_key:
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if node is not lru._least_recently_used:
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raise AssertionError('only the last node should have'
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' no next value: %s' % (node,))
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node_next = lru._cache[node.next_key]
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if node_next.prev is not node:
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raise AssertionError('inconsistency found, node.next.prev'
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' != node: %s' % (node,))
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if node is not lru._most_recently_used:
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raise AssertionError('only the _most_recently_used should'
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' not have a previous node: %s'
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if node.prev.next_key != node.key:
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raise AssertionError('inconsistency found, node.prev.next'
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' != node: %s' % (node,))
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class TestLRUCache(tests.TestCase):
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"""Test that LRU cache properly keeps track of entries."""
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def test_cache_size(self):
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cache = lru_cache.LRUCache(max_cache=10)
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self.assertEqual(10, cache.cache_size())
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cache = lru_cache.LRUCache(max_cache=256)
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self.assertEqual(256, cache.cache_size())
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self.assertEqual(512, cache.cache_size())
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def test_missing(self):
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cache = lru_cache.LRUCache(max_cache=10)
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self.assertFalse('foo' in cache)
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self.assertRaises(KeyError, cache.__getitem__, 'foo')
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self.assertEqual('bar', cache['foo'])
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self.assertTrue('foo' in cache)
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self.assertFalse('bar' in cache)
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def test_map_None(self):
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# Make sure that we can properly map None as a key.
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cache = lru_cache.LRUCache(max_cache=10)
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self.assertFalse(None in cache)
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self.assertEqual(1, cache[None])
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self.assertEqual(2, cache[None])
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# Test the various code paths of __getitem__, to make sure that we can
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# handle when None is the key for the LRU and the MRU
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self.assertEqual([None, 1], [n.key for n in walk_lru(cache)])
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def test_add__null_key(self):
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cache = lru_cache.LRUCache(max_cache=10)
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self.assertRaises(ValueError,
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cache.__setitem__, lru_cache._null_key, 1)
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def test_overflow(self):
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"""Adding extra entries will pop out old ones."""
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cache = lru_cache.LRUCache(max_cache=1, after_cleanup_count=1)
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# With a max cache of 1, adding 'baz' should pop out 'foo'
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self.assertFalse('foo' in cache)
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self.assertTrue('baz' in cache)
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self.assertEqual('biz', cache['baz'])
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def test_by_usage(self):
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"""Accessing entries bumps them up in priority."""
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cache = lru_cache.LRUCache(max_cache=2)
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self.assertEqual('biz', cache['baz'])
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# This must kick out 'foo' because it was the last accessed
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self.assertFalse('foo' in cache)
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cache = lru_cache.LRUCache(max_cache=10, after_cleanup_count=10)
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self.assertEqual(4, len(cache))
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self.assertEqual(8, len(cache))
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cache[1] = 15 # replacement
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self.assertEqual(8, len(cache))
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self.assertEqual(10, len(cache))
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self.assertEqual([11, 10, 9, 1, 8, 7, 6, 5, 4, 3],
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[n.key for n in walk_lru(cache)])
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def test_cleanup_shrinks_to_after_clean_count(self):
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cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=3)
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self.assertEqual(5, len(cache))
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# This will bump us over the max, which causes us to shrink down to
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# after_cleanup_cache size
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self.assertEqual(3, len(cache))
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def test_after_cleanup_larger_than_max(self):
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cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=10)
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self.assertEqual(5, cache._after_cleanup_count)
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def test_after_cleanup_none(self):
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cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=None)
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# By default _after_cleanup_size is 80% of the normal size
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self.assertEqual(4, cache._after_cleanup_count)
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def test_cleanup(self):
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cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=2)
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self.assertEqual(5, len(cache))
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self.assertEqual(2, len(cache))
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def test_preserve_last_access_order(self):
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cache = lru_cache.LRUCache(max_cache=5)
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self.assertEqual([5, 4, 3, 2, 1], [n.key for n in walk_lru(cache)])
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# Now access some randomly
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self.assertEqual([2, 3, 5, 4, 1], [n.key for n in walk_lru(cache)])
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cache = lru_cache.LRUCache(max_cache=5)
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self.assertEqual(20, cache.get(2))
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self.assertIs(None, cache.get(3))
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self.assertIs(obj, cache.get(3, obj))
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self.assertEqual([2, 1], [n.key for n in walk_lru(cache)])
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self.assertEqual(10, cache.get(1))
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self.assertEqual([1, 2], [n.key for n in walk_lru(cache)])
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cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=5)
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self.assertEqual([1, 2, 3], sorted(cache.keys()))
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self.assertEqual([2, 3, 4, 5, 6], sorted(cache.keys()))
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def test_resize_smaller(self):
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cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=4)
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self.assertEqual([1, 2, 3, 4, 5], sorted(cache.keys()))
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self.assertEqual([3, 4, 5, 6], sorted(cache.keys()))
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# Now resize to something smaller, which triggers a cleanup
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cache.resize(max_cache=3, after_cleanup_count=2)
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self.assertEqual([5, 6], sorted(cache.keys()))
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# Adding something will use the new size
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self.assertEqual([5, 6, 7], sorted(cache.keys()))
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self.assertEqual([7, 8], sorted(cache.keys()))
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def test_resize_larger(self):
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cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=4)
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self.assertEqual([1, 2, 3, 4, 5], sorted(cache.keys()))
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self.assertEqual([3, 4, 5, 6], sorted(cache.keys()))
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cache.resize(max_cache=8, after_cleanup_count=6)
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self.assertEqual([3, 4, 5, 6], sorted(cache.keys()))
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self.assertEqual([3, 4, 5, 6, 7, 8, 9, 10], sorted(cache.keys()))
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cache[11] = 12 # triggers cleanup back to new after_cleanup_count
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self.assertEqual([6, 7, 8, 9, 10, 11], sorted(cache.keys()))
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class TestLRUSizeCache(tests.TestCase):
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def test_basic_init(self):
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cache = lru_cache.LRUSizeCache()
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self.assertEqual(2048, cache._max_cache)
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self.assertEqual(int(cache._max_size * 0.8), cache._after_cleanup_size)
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self.assertEqual(0, cache._value_size)
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def test_add__null_key(self):
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cache = lru_cache.LRUSizeCache()
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self.assertRaises(ValueError,
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cache.__setitem__, lru_cache._null_key, 1)
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def test_add_tracks_size(self):
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cache = lru_cache.LRUSizeCache()
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self.assertEqual(0, cache._value_size)
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cache['my key'] = 'my value text'
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self.assertEqual(13, cache._value_size)
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def test_remove_tracks_size(self):
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cache = lru_cache.LRUSizeCache()
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self.assertEqual(0, cache._value_size)
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cache['my key'] = 'my value text'
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self.assertEqual(13, cache._value_size)
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node = cache._cache['my key']
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cache._remove_node(node)
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self.assertEqual(0, cache._value_size)
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def test_no_add_over_size(self):
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"""Adding a large value may not be cached at all."""
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cache = lru_cache.LRUSizeCache(max_size=10, after_cleanup_size=5)
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self.assertEqual(0, cache._value_size)
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self.assertEqual({}, cache.as_dict())
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cache['test'] = 'key'
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self.assertEqual(3, cache._value_size)
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self.assertEqual({'test': 'key'}, cache.as_dict())
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cache['test2'] = 'key that is too big'
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self.assertEqual(3, cache._value_size)
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self.assertEqual({'test': 'key'}, cache.as_dict())
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# If we would add a key, only to cleanup and remove all cached entries,
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# then obviously that value should not be stored
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cache['test3'] = 'bigkey'
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self.assertEqual(3, cache._value_size)
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self.assertEqual({'test': 'key'}, cache.as_dict())
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cache['test4'] = 'bikey'
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self.assertEqual(3, cache._value_size)
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self.assertEqual({'test': 'key'}, cache.as_dict())
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def test_adding_clears_cache_based_on_size(self):
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"""The cache is cleared in LRU order until small enough"""
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cache = lru_cache.LRUSizeCache(max_size=20)
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cache['key1'] = 'value' # 5 chars
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cache['key2'] = 'value2' # 6 chars
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cache['key3'] = 'value23' # 7 chars
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self.assertEqual(5 + 6 + 7, cache._value_size)
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cache['key2'] # reference key2 so it gets a newer reference time
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cache['key4'] = 'value234' # 8 chars, over limit
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# We have to remove 2 keys to get back under limit
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self.assertEqual(6 + 8, cache._value_size)
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self.assertEqual({'key2': 'value2', 'key4': 'value234'},
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def test_adding_clears_to_after_cleanup_size(self):
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cache = lru_cache.LRUSizeCache(max_size=20, after_cleanup_size=10)
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cache['key1'] = 'value' # 5 chars
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cache['key2'] = 'value2' # 6 chars
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cache['key3'] = 'value23' # 7 chars
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self.assertEqual(5 + 6 + 7, cache._value_size)
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cache['key2'] # reference key2 so it gets a newer reference time
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cache['key4'] = 'value234' # 8 chars, over limit
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# We have to remove 3 keys to get back under limit
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self.assertEqual(8, cache._value_size)
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self.assertEqual({'key4': 'value234'}, cache.as_dict())
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def test_custom_sizes(self):
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def size_of_list(lst):
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return sum(len(x) for x in lst)
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cache = lru_cache.LRUSizeCache(max_size=20, after_cleanup_size=10,
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compute_size=size_of_list)
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cache['key1'] = ['val', 'ue'] # 5 chars
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cache['key2'] = ['val', 'ue2'] # 6 chars
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cache['key3'] = ['val', 'ue23'] # 7 chars
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self.assertEqual(5 + 6 + 7, cache._value_size)
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cache['key2'] # reference key2 so it gets a newer reference time
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cache['key4'] = ['value', '234'] # 8 chars, over limit
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# We have to remove 3 keys to get back under limit
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self.assertEqual(8, cache._value_size)
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self.assertEqual({'key4': ['value', '234']}, cache.as_dict())
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def test_cleanup(self):
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cache = lru_cache.LRUSizeCache(max_size=20, after_cleanup_size=10)
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cache['key1'] = 'value' # 5 chars
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cache['key2'] = 'value2' # 6 chars
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cache['key3'] = 'value23' # 7 chars
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self.assertEqual(5 + 6 + 7, cache._value_size)
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# Only the most recent fits after cleaning up
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self.assertEqual(7, cache._value_size)
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cache = lru_cache.LRUSizeCache(max_size=10)
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self.assertEqual([1, 2, 3], sorted(cache.keys()))
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def test_resize_smaller(self):
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cache = lru_cache.LRUSizeCache(max_size=10, after_cleanup_size=9)
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self.assertEqual([2, 3, 4], sorted(cache.keys()))
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# Resize should also cleanup again
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cache.resize(max_size=6, after_cleanup_size=4)
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self.assertEqual([4], sorted(cache.keys()))
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# Adding should use the new max size
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self.assertEqual([4, 5], sorted(cache.keys()))
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self.assertEqual([6], sorted(cache.keys()))
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def test_resize_larger(self):
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cache = lru_cache.LRUSizeCache(max_size=10, after_cleanup_size=9)
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self.assertEqual([2, 3, 4], sorted(cache.keys()))
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cache.resize(max_size=15, after_cleanup_size=12)
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self.assertEqual([2, 3, 4], sorted(cache.keys()))
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self.assertEqual([2, 3, 4, 5, 6], sorted(cache.keys()))
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self.assertEqual([4, 5, 6, 7], sorted(cache.keys()))
added
removed
breezy/tests/test_lru_cache.py
