~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2006, 2008, 2009 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Tests for the lru_cache module."""

from bzrlib import (

    lru_cache,

    symbol_versioning,

    tests,

    )

def walk_lru(lru):

    """Test helper to walk the LRU list and assert its consistency"""

    node = lru._most_recently_used

    if node is not None:

        if node.prev is not None:

            raise AssertionError('the _most_recently_used entry is not'

                                 ' supposed to have a previous entry'

                                 ' %s' % (node,))

    while node is not None:

        if node.next_key is lru_cache._null_key:

            if node is not lru._least_recently_used:

                raise AssertionError('only the last node should have'

                                     ' no next value: %s' % (node,))

            node_next = None

        else:

            node_next = lru._cache[node.next_key]

            if node_next.prev is not node:

                raise AssertionError('inconsistency found, node.next.prev'

                                     ' != node: %s' % (node,))

        if node.prev is None:

            if node is not lru._most_recently_used:

                raise AssertionError('only the _most_recently_used should'

                                     ' not have a previous node: %s'

                                     % (node,))

        else:

            if node.prev.next_key != node.key:

                raise AssertionError('inconsistency found, node.prev.next'

                                     ' != node: %s' % (node,))

        yield node

        node = node_next

class TestLRUCache(tests.TestCase):

    """Test that LRU cache properly keeps track of entries."""

    def test_cache_size(self):

        cache = lru_cache.LRUCache(max_cache=10)

        self.assertEqual(10, cache.cache_size())

        cache = lru_cache.LRUCache(max_cache=256)

        self.assertEqual(256, cache.cache_size())

        cache.resize(512)

        self.assertEqual(512, cache.cache_size())

    def test_missing(self):

        cache = lru_cache.LRUCache(max_cache=10)

        self.assertFalse('foo' in cache)

        self.assertRaises(KeyError, cache.__getitem__, 'foo')

        cache['foo'] = 'bar'

        self.assertEqual('bar', cache['foo'])

        self.assertTrue('foo' in cache)

        self.assertFalse('bar' in cache)

    def test_map_None(self):

        # Make sure that we can properly map None as a key.

        cache = lru_cache.LRUCache(max_cache=10)

        self.assertFalse(None in cache)

        cache[None] = 1

        self.assertEqual(1, cache[None])

        cache[None] = 2

        self.assertEqual(2, cache[None])

        # Test the various code paths of __getitem__, to make sure that we can

        # handle when None is the key for the LRU and the MRU

        cache[1] = 3

        cache[None] = 1

        cache[None]

        cache[1]

        cache[None]

        self.assertEqual([None, 1], [n.key for n in walk_lru(cache)])

    def test_add__null_key(self):

        cache = lru_cache.LRUCache(max_cache=10)

        self.assertRaises(ValueError,

            cache.__setitem__, lru_cache._null_key, 1)

    def test_overflow(self):

        """Adding extra entries will pop out old ones."""

        cache = lru_cache.LRUCache(max_cache=1, after_cleanup_count=1)

        cache['foo'] = 'bar'

        # With a max cache of 1, adding 'baz' should pop out 'foo'

        cache['baz'] = 'biz'

        self.assertFalse('foo' in cache)

        self.assertTrue('baz' in cache)

        self.assertEqual('biz', cache['baz'])

    def test_by_usage(self):

        """Accessing entries bumps them up in priority."""

        cache = lru_cache.LRUCache(max_cache=2)

        cache['baz'] = 'biz'

        cache['foo'] = 'bar'

        self.assertEqual('biz', cache['baz'])

        # This must kick out 'foo' because it was the last accessed

        cache['nub'] = 'in'

        self.assertFalse('foo' in cache)

    def test_cleanup_function_deprecated(self):

        """Test that per-node cleanup functions are no longer allowed"""

        cache = lru_cache.LRUCache()

        self.assertRaises(ValueError, self.applyDeprecated,

            symbol_versioning.deprecated_in((2, 5, 0)),

            cache.add, "key", 1, cleanup=lambda: None)

    def test_len(self):

        cache = lru_cache.LRUCache(max_cache=10, after_cleanup_count=10)

        cache[1] = 10

        cache[2] = 20

        cache[3] = 30

        cache[4] = 40

        self.assertEqual(4, len(cache))

        cache[5] = 50

        cache[6] = 60

        cache[7] = 70

        cache[8] = 80

        self.assertEqual(8, len(cache))

        cache[1] = 15 # replacement

        self.assertEqual(8, len(cache))

        cache[9] = 90

        cache[10] = 100

        cache[11] = 110

        # We hit the max

        self.assertEqual(10, len(cache))

        self.assertEqual([11, 10, 9, 1, 8, 7, 6, 5, 4, 3],

                         [n.key for n in walk_lru(cache)])

    def test_cleanup_shrinks_to_after_clean_count(self):

        cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=3)

        cache[1] = 10

        cache[2] = 20

        cache[3] = 25

        cache[4] = 30

        cache[5] = 35

        self.assertEqual(5, len(cache))

        # This will bump us over the max, which causes us to shrink down to

        # after_cleanup_cache size

        cache[6] = 40

        self.assertEqual(3, len(cache))

    def test_after_cleanup_larger_than_max(self):

        cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=10)

        self.assertEqual(5, cache._after_cleanup_count)

    def test_after_cleanup_none(self):

        cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=None)

        # By default _after_cleanup_size is 80% of the normal size

        self.assertEqual(4, cache._after_cleanup_count)

    def test_cleanup(self):

        cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=2)

        # Add these in order

        cache[1] = 10

        cache[2] = 20

        cache[3] = 25

        cache[4] = 30

        cache[5] = 35

        self.assertEqual(5, len(cache))

        # Force a compaction

        cache.cleanup()

        self.assertEqual(2, len(cache))

    def test_preserve_last_access_order(self):

        cache = lru_cache.LRUCache(max_cache=5)

        # Add these in order

        cache[1] = 10

        cache[2] = 20

        cache[3] = 25

        cache[4] = 30

        cache[5] = 35

        self.assertEqual([5, 4, 3, 2, 1], [n.key for n in walk_lru(cache)])

        # Now access some randomly

        cache[2]

        cache[5]

        cache[3]

        cache[2]

        self.assertEqual([2, 3, 5, 4, 1], [n.key for n in walk_lru(cache)])

    def test_get(self):

        cache = lru_cache.LRUCache(max_cache=5)

        cache[1] = 10

        cache[2] = 20

        self.assertEqual(20, cache.get(2))

        self.assertIs(None, cache.get(3))

        obj = object()

        self.assertIs(obj, cache.get(3, obj))

        self.assertEqual([2, 1], [n.key for n in walk_lru(cache)])

        self.assertEqual(10, cache.get(1))

        self.assertEqual([1, 2], [n.key for n in walk_lru(cache)])

    def test_keys(self):

        cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=5)

        cache[1] = 2

        cache[2] = 3

        cache[3] = 4

        self.assertEqual([1, 2, 3], sorted(cache.keys()))

        cache[4] = 5

        cache[5] = 6

        cache[6] = 7

        self.assertEqual([2, 3, 4, 5, 6], sorted(cache.keys()))

    def test_resize_smaller(self):

        cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=4)

        cache[1] = 2

        cache[2] = 3

        cache[3] = 4

        cache[4] = 5

        cache[5] = 6

        self.assertEqual([1, 2, 3, 4, 5], sorted(cache.keys()))

        cache[6] = 7

        self.assertEqual([3, 4, 5, 6], sorted(cache.keys()))

        # Now resize to something smaller, which triggers a cleanup

        cache.resize(max_cache=3, after_cleanup_count=2)

        self.assertEqual([5, 6], sorted(cache.keys()))

        # Adding something will use the new size

        cache[7] = 8

        self.assertEqual([5, 6, 7], sorted(cache.keys()))

        cache[8] = 9

        self.assertEqual([7, 8], sorted(cache.keys()))

    def test_resize_larger(self):

        cache = lru_cache.LRUCache(max_cache=5, after_cleanup_count=4)

        cache[1] = 2

        cache[2] = 3

        cache[3] = 4

        cache[4] = 5

        cache[5] = 6

        self.assertEqual([1, 2, 3, 4, 5], sorted(cache.keys()))

        cache[6] = 7

        self.assertEqual([3, 4, 5, 6], sorted(cache.keys()))

        cache.resize(max_cache=8, after_cleanup_count=6)

        self.assertEqual([3, 4, 5, 6], sorted(cache.keys()))

        cache[7] = 8

        cache[8] = 9

        cache[9] = 10

        cache[10] = 11

        self.assertEqual([3, 4, 5, 6, 7, 8, 9, 10], sorted(cache.keys()))

        cache[11] = 12 # triggers cleanup back to new after_cleanup_count

        self.assertEqual([6, 7, 8, 9, 10, 11], sorted(cache.keys()))

class TestLRUSizeCache(tests.TestCase):

    def test_basic_init(self):

        cache = lru_cache.LRUSizeCache()

        self.assertEqual(2048, cache._max_cache)

        self.assertEqual(int(cache._max_size*0.8), cache._after_cleanup_size)

        self.assertEqual(0, cache._value_size)

    def test_add__null_key(self):

        cache = lru_cache.LRUSizeCache()

        self.assertRaises(ValueError,

            cache.__setitem__, lru_cache._null_key, 1)

    def test_add_tracks_size(self):

        cache = lru_cache.LRUSizeCache()

        self.assertEqual(0, cache._value_size)

        cache['my key'] = 'my value text'

        self.assertEqual(13, cache._value_size)

    def test_remove_tracks_size(self):

        cache = lru_cache.LRUSizeCache()

        self.assertEqual(0, cache._value_size)

        cache['my key'] = 'my value text'

        self.assertEqual(13, cache._value_size)

        node = cache._cache['my key']

        cache._remove_node(node)

        self.assertEqual(0, cache._value_size)

    def test_no_add_over_size(self):

        """Adding a large value may not be cached at all."""

        cache = lru_cache.LRUSizeCache(max_size=10, after_cleanup_size=5)

        self.assertEqual(0, cache._value_size)

        self.assertEqual({}, cache.as_dict())

        cache['test'] = 'key'

        self.assertEqual(3, cache._value_size)

        self.assertEqual({'test': 'key'}, cache.as_dict())

        cache['test2'] = 'key that is too big'

        self.assertEqual(3, cache._value_size)

        self.assertEqual({'test':'key'}, cache.as_dict())

        # If we would add a key, only to cleanup and remove all cached entries,

        # then obviously that value should not be stored

        cache['test3'] = 'bigkey'

        self.assertEqual(3, cache._value_size)

        self.assertEqual({'test':'key'}, cache.as_dict())

        cache['test4'] = 'bikey'

        self.assertEqual(3, cache._value_size)

        self.assertEqual({'test':'key'}, cache.as_dict())

    def test_adding_clears_cache_based_on_size(self):

        """The cache is cleared in LRU order until small enough"""

        cache = lru_cache.LRUSizeCache(max_size=20)

        cache['key1'] = 'value' # 5 chars

        cache['key2'] = 'value2' # 6 chars

        cache['key3'] = 'value23' # 7 chars

        self.assertEqual(5+6+7, cache._value_size)

        cache['key2'] # reference key2 so it gets a newer reference time

        cache['key4'] = 'value234' # 8 chars, over limit

        # We have to remove 2 keys to get back under limit

        self.assertEqual(6+8, cache._value_size)

        self.assertEqual({'key2':'value2', 'key4':'value234'},

                         cache.as_dict())

    def test_adding_clears_to_after_cleanup_size(self):

        cache = lru_cache.LRUSizeCache(max_size=20, after_cleanup_size=10)

        cache['key1'] = 'value' # 5 chars

        cache['key2'] = 'value2' # 6 chars

        cache['key3'] = 'value23' # 7 chars

        self.assertEqual(5+6+7, cache._value_size)

        cache['key2'] # reference key2 so it gets a newer reference time

        cache['key4'] = 'value234' # 8 chars, over limit

        # We have to remove 3 keys to get back under limit

        self.assertEqual(8, cache._value_size)

        self.assertEqual({'key4':'value234'}, cache.as_dict())

    def test_custom_sizes(self):

        def size_of_list(lst):

            return sum(len(x) for x in lst)

        cache = lru_cache.LRUSizeCache(max_size=20, after_cleanup_size=10,

                                       compute_size=size_of_list)

        cache['key1'] = ['val', 'ue'] # 5 chars

        cache['key2'] = ['val', 'ue2'] # 6 chars

        cache['key3'] = ['val', 'ue23'] # 7 chars

        self.assertEqual(5+6+7, cache._value_size)

        cache['key2'] # reference key2 so it gets a newer reference time

        cache['key4'] = ['value', '234'] # 8 chars, over limit

        # We have to remove 3 keys to get back under limit

        self.assertEqual(8, cache._value_size)

        self.assertEqual({'key4':['value', '234']}, cache.as_dict())

    def test_cleanup(self):

        cache = lru_cache.LRUSizeCache(max_size=20, after_cleanup_size=10)

        # Add these in order

        cache['key1'] = 'value' # 5 chars

        cache['key2'] = 'value2' # 6 chars

        cache['key3'] = 'value23' # 7 chars

        self.assertEqual(5+6+7, cache._value_size)

        cache.cleanup()

        # Only the most recent fits after cleaning up

        self.assertEqual(7, cache._value_size)

    def test_keys(self):

        cache = lru_cache.LRUSizeCache(max_size=10)

        cache[1] = 'a'

        cache[2] = 'b'

        cache[3] = 'cdef'

        self.assertEqual([1, 2, 3], sorted(cache.keys()))

    def test_resize_smaller(self):

        cache = lru_cache.LRUSizeCache(max_size=10, after_cleanup_size=9)

        cache[1] = 'abc'

        cache[2] = 'def'

        cache[3] = 'ghi'

        cache[4] = 'jkl'

        # Triggers a cleanup

        self.assertEqual([2, 3, 4], sorted(cache.keys()))

        # Resize should also cleanup again

        cache.resize(max_size=6, after_cleanup_size=4)

        self.assertEqual([4], sorted(cache.keys()))

        # Adding should use the new max size

        cache[5] = 'mno'

        self.assertEqual([4, 5], sorted(cache.keys()))

        cache[6] = 'pqr'

        self.assertEqual([6], sorted(cache.keys()))

    def test_resize_larger(self):

        cache = lru_cache.LRUSizeCache(max_size=10, after_cleanup_size=9)

        cache[1] = 'abc'

        cache[2] = 'def'

        cache[3] = 'ghi'

        cache[4] = 'jkl'

        # Triggers a cleanup

        self.assertEqual([2, 3, 4], sorted(cache.keys()))

        cache.resize(max_size=15, after_cleanup_size=12)

        self.assertEqual([2, 3, 4], sorted(cache.keys()))

        cache[5] = 'mno'

        cache[6] = 'pqr'

        self.assertEqual([2, 3, 4, 5, 6], sorted(cache.keys()))

        cache[7] = 'stu'

        self.assertEqual([4, 5, 6, 7], sorted(cache.keys()))