17
17
"""Tests for the lru_cache module."""
26
"""Test helper to walk the LRU list and assert its consistency"""
27
node = lru._most_recently_used
29
if node.prev is not None:
30
raise AssertionError('the _most_recently_used entry is not'
31
' supposed to have a previous entry'
33
while node is not None:
34
if node.next_key is lru_cache._null_key:
35
if node is not lru._least_recently_used:
36
raise AssertionError('only the last node should have'
37
' no next value: %s' % (node,))
40
node_next = lru._cache[node.next_key]
41
if node_next.prev is not node:
42
raise AssertionError('inconsistency found, node.next.prev'
43
' != node: %s' % (node,))
45
if node is not lru._most_recently_used:
46
raise AssertionError('only the _most_recently_used should'
47
' not have a previous node: %s'
50
if node.prev.next_key != node.key:
51
raise AssertionError('inconsistency found, node.prev.next'
52
' != node: %s' % (node,))
25
57
class TestLRUCache(tests.TestCase):
26
58
"""Test that LRU cache properly keeps track of entries."""
92
125
# This must kick out 'foo' because it was the last accessed
93
126
cache['nub'] = 'in'
95
self.failIf('foo' in cache)
97
def test_cleanup(self):
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"""Test that we can use a cleanup function."""
100
def cleanup_func(key, val):
101
cleanup_called.append((key, val))
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cache = lru_cache.LRUCache(max_cache=2)
105
cache.add('baz', '1', cleanup=cleanup_func)
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cache.add('foo', '2', cleanup=cleanup_func)
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cache.add('biz', '3', cleanup=cleanup_func)
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self.assertEqual([('baz', '1')], cleanup_called)
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# 'foo' is now most recent, so final cleanup will call it last
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self.assertEqual([('baz', '1'), ('biz', '3'), ('foo', '2')],
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def test_cleanup_on_replace(self):
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"""Replacing an object should cleanup the old value."""
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def cleanup_func(key, val):
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cleanup_called.append((key, val))
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cache = lru_cache.LRUCache(max_cache=2)
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cache.add(1, 10, cleanup=cleanup_func)
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cache.add(2, 20, cleanup=cleanup_func)
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cache.add(2, 25, cleanup=cleanup_func)
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self.assertEqual([(2, 20)], cleanup_called)
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self.assertEqual(25, cache[2])
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# Even __setitem__ should make sure cleanup() is called
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self.assertEqual([(2, 20), (2, 25)], cleanup_called)
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def test_cleanup_error_maintains_linked_list(self):
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def cleanup_func(key, val):
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cleanup_called.append((key, val))
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raise ValueError('failure during cleanup')
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cache = lru_cache.LRUCache(max_cache=10)
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cache.add(i, i, cleanup=cleanup_func)
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for i in xrange(10, 20):
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self.assertRaises(ValueError,
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cache.add, i, i, cleanup=cleanup_func)
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self.assertEqual([(i, i) for i in xrange(10)], cleanup_called)
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self.assertEqual(range(19, 9, -1), [n.key for n in cache._walk_lru()])
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def test_cleanup_during_replace_still_replaces(self):
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def cleanup_func(key, val):
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cleanup_called.append((key, val))
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raise ValueError('failure during cleanup')
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cache = lru_cache.LRUCache(max_cache=10)
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cache.add(i, i, cleanup=cleanup_func)
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self.assertRaises(ValueError,
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cache.add, 1, 20, cleanup=cleanup_func)
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# We also still update the recent access to this node
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self.assertEqual([1, 9, 8, 7, 6, 5, 4, 3, 2, 0],
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[n.key for n in cache._walk_lru()])
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self.assertEqual(20, cache[1])
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self.assertEqual([(1, 1)], cleanup_called)
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self.assertEqual([1, 9, 8, 7, 6, 5, 4, 3, 2, 0],
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[n.key for n in cache._walk_lru()])
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self.assertFalse('foo' in cache)
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130
def test_len(self):
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cache = lru_cache.LRUCache(max_cache=10, after_cleanup_count=10)
198
156
self.assertEqual(10, len(cache))
199
157
self.assertEqual([11, 10, 9, 1, 8, 7, 6, 5, 4, 3],
200
[n.key for n in cache._walk_lru()])
158
[n.key for n in walk_lru(cache)])
202
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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)
211
169
self.assertEqual(5, len(cache))
212
170
# This will bump us over the max, which causes us to shrink down to
213
171
# after_cleanup_cache size
215
173
self.assertEqual(3, len(cache))
217
175
def test_after_cleanup_larger_than_max(self):
242
200
cache = lru_cache.LRUCache(max_cache=5)
244
202
# Add these in order
251
self.assertEqual([5, 4, 3, 2, 1], [n.key for n in cache._walk_lru()])
209
self.assertEqual([5, 4, 3, 2, 1], [n.key for n in walk_lru(cache)])
253
211
# Now access some randomly
258
self.assertEqual([2, 3, 5, 4, 1], [n.key for n in cache._walk_lru()])
216
self.assertEqual([2, 3, 5, 4, 1], [n.key for n in walk_lru(cache)])
260
218
def test_get(self):
261
219
cache = lru_cache.LRUCache(max_cache=5)
265
223
self.assertEqual(20, cache.get(2))
266
224
self.assertIs(None, cache.get(3))
268
226
self.assertIs(obj, cache.get(3, obj))
269
self.assertEqual([2, 1], [n.key for n in cache._walk_lru()])
227
self.assertEqual([2, 1], [n.key for n in walk_lru(cache)])
270
228
self.assertEqual(10, cache.get(1))
271
self.assertEqual([1, 2], [n.key for n in cache._walk_lru()])
229
self.assertEqual([1, 2], [n.key for n in walk_lru(cache)])
273
231
def test_keys(self):
274
232
cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=5)
340
291
def test_add__null_key(self):
341
292
cache = lru_cache.LRUSizeCache()
342
self.assertRaises(ValueError, cache.add, lru_cache._null_key, 1)
293
self.assertRaises(ValueError,
294
cache.__setitem__, lru_cache._null_key, 1)
344
296
def test_add_tracks_size(self):
345
297
cache = lru_cache.LRUSizeCache()
346
298
self.assertEqual(0, cache._value_size)
347
cache.add('my key', 'my value text')
299
cache['my key'] = 'my value text'
348
300
self.assertEqual(13, cache._value_size)
350
302
def test_remove_tracks_size(self):
351
303
cache = lru_cache.LRUSizeCache()
352
304
self.assertEqual(0, cache._value_size)
353
cache.add('my key', 'my value text')
305
cache['my key'] = 'my value text'
354
306
self.assertEqual(13, cache._value_size)
355
307
node = cache._cache['my key']
356
308
cache._remove_node(node)
360
312
"""Adding a large value may not be cached at all."""
361
313
cache = lru_cache.LRUSizeCache(max_size=10, after_cleanup_size=5)
362
314
self.assertEqual(0, cache._value_size)
363
self.assertEqual({}, cache.items())
364
cache.add('test', 'key')
365
self.assertEqual(3, cache._value_size)
366
self.assertEqual({'test': 'key'}, cache.items())
367
cache.add('test2', 'key that is too big')
368
self.assertEqual(3, cache._value_size)
369
self.assertEqual({'test':'key'}, cache.items())
315
self.assertEqual({}, cache.as_dict())
316
cache['test'] = 'key'
317
self.assertEqual(3, cache._value_size)
318
self.assertEqual({'test': 'key'}, cache.as_dict())
319
cache['test2'] = 'key that is too big'
320
self.assertEqual(3, cache._value_size)
321
self.assertEqual({'test':'key'}, cache.as_dict())
370
322
# If we would add a key, only to cleanup and remove all cached entries,
371
323
# then obviously that value should not be stored
372
cache.add('test3', 'bigkey')
373
self.assertEqual(3, cache._value_size)
374
self.assertEqual({'test':'key'}, cache.items())
376
cache.add('test4', 'bikey')
377
self.assertEqual(3, cache._value_size)
378
self.assertEqual({'test':'key'}, cache.items())
380
def test_no_add_over_size_cleanup(self):
381
"""If a large value is not cached, we will call cleanup right away."""
383
def cleanup(key, value):
384
cleanup_calls.append((key, value))
386
cache = lru_cache.LRUSizeCache(max_size=10, after_cleanup_size=5)
387
self.assertEqual(0, cache._value_size)
388
self.assertEqual({}, cache.items())
389
cache.add('test', 'key that is too big', cleanup=cleanup)
391
self.assertEqual(0, cache._value_size)
392
self.assertEqual({}, cache.items())
393
# and cleanup was called
394
self.assertEqual([('test', 'key that is too big')], cleanup_calls)
324
cache['test3'] = 'bigkey'
325
self.assertEqual(3, cache._value_size)
326
self.assertEqual({'test':'key'}, cache.as_dict())
328
cache['test4'] = 'bikey'
329
self.assertEqual(3, cache._value_size)
330
self.assertEqual({'test':'key'}, cache.as_dict())
396
332
def test_adding_clears_cache_based_on_size(self):
397
333
"""The cache is cleared in LRU order until small enough"""
398
334
cache = lru_cache.LRUSizeCache(max_size=20)
399
cache.add('key1', 'value') # 5 chars
400
cache.add('key2', 'value2') # 6 chars
401
cache.add('key3', 'value23') # 7 chars
335
cache['key1'] = 'value' # 5 chars
336
cache['key2'] = 'value2' # 6 chars
337
cache['key3'] = 'value23' # 7 chars
402
338
self.assertEqual(5+6+7, cache._value_size)
403
339
cache['key2'] # reference key2 so it gets a newer reference time
404
cache.add('key4', 'value234') # 8 chars, over limit
340
cache['key4'] = 'value234' # 8 chars, over limit
405
341
# We have to remove 2 keys to get back under limit
406
342
self.assertEqual(6+8, cache._value_size)
407
343
self.assertEqual({'key2':'value2', 'key4':'value234'},
410
346
def test_adding_clears_to_after_cleanup_size(self):
411
347
cache = lru_cache.LRUSizeCache(max_size=20, after_cleanup_size=10)
412
cache.add('key1', 'value') # 5 chars
413
cache.add('key2', 'value2') # 6 chars
414
cache.add('key3', 'value23') # 7 chars
348
cache['key1'] = 'value' # 5 chars
349
cache['key2'] = 'value2' # 6 chars
350
cache['key3'] = 'value23' # 7 chars
415
351
self.assertEqual(5+6+7, cache._value_size)
416
352
cache['key2'] # reference key2 so it gets a newer reference time
417
cache.add('key4', 'value234') # 8 chars, over limit
353
cache['key4'] = 'value234' # 8 chars, over limit
418
354
# We have to remove 3 keys to get back under limit
419
355
self.assertEqual(8, cache._value_size)
420
self.assertEqual({'key4':'value234'}, cache.items())
356
self.assertEqual({'key4':'value234'}, cache.as_dict())
422
358
def test_custom_sizes(self):
423
359
def size_of_list(lst):
425
361
cache = lru_cache.LRUSizeCache(max_size=20, after_cleanup_size=10,
426
362
compute_size=size_of_list)
428
cache.add('key1', ['val', 'ue']) # 5 chars
429
cache.add('key2', ['val', 'ue2']) # 6 chars
430
cache.add('key3', ['val', 'ue23']) # 7 chars
364
cache['key1'] = ['val', 'ue'] # 5 chars
365
cache['key2'] = ['val', 'ue2'] # 6 chars
366
cache['key3'] = ['val', 'ue23'] # 7 chars
431
367
self.assertEqual(5+6+7, cache._value_size)
432
368
cache['key2'] # reference key2 so it gets a newer reference time
433
cache.add('key4', ['value', '234']) # 8 chars, over limit
369
cache['key4'] = ['value', '234'] # 8 chars, over limit
434
370
# We have to remove 3 keys to get back under limit
435
371
self.assertEqual(8, cache._value_size)
436
self.assertEqual({'key4':['value', '234']}, cache.items())
372
self.assertEqual({'key4':['value', '234']}, cache.as_dict())
438
374
def test_cleanup(self):
439
375
cache = lru_cache.LRUSizeCache(max_size=20, after_cleanup_size=10)
441
377
# Add these in order
442
cache.add('key1', 'value') # 5 chars
443
cache.add('key2', 'value2') # 6 chars
444
cache.add('key3', 'value23') # 7 chars
378
cache['key1'] = 'value' # 5 chars
379
cache['key2'] = 'value2' # 6 chars
380
cache['key3'] = 'value23' # 7 chars
445
381
self.assertEqual(5+6+7, cache._value_size)