test_core.py

"""Test diskcache.core.Cache."""

import errno
import hashlib
import io
import os
import os.path as op
import pickle
import shutil
import sqlite3
import subprocess as sp
import tempfile
import threading
import time
import warnings
from unittest import mock

import pytest

import diskcache as dc

pytestmark = pytest.mark.filterwarnings('ignore', category=dc.EmptyDirWarning)


@pytest.fixture
def cache():
    with dc.Cache() as cache:
        yield cache
    shutil.rmtree(cache.directory, ignore_errors=True)


def test_init(cache):
    for key, value in dc.DEFAULT_SETTINGS.items():
        assert getattr(cache, key) == value
    cache.check()
    cache.close()
    cache.close()


def test_init_disk():
    with dc.Cache(disk_pickle_protocol=1, disk_min_file_size=2 ** 20) as cache:
        key = (None, 0, 'abc')
        cache[key] = 0
        cache.check()
        assert cache.disk_min_file_size == 2 ** 20
        assert cache.disk_pickle_protocol == 1
    shutil.rmtree(cache.directory, ignore_errors=True)


def test_disk_reset():
    with dc.Cache(disk_min_file_size=0, disk_pickle_protocol=0) as cache:
        value = (None, 0, 'abc')

        cache[0] = value
        cache.check()

        assert cache.disk_min_file_size == 0
        assert cache.disk_pickle_protocol == 0
        assert cache._disk.min_file_size == 0
        assert cache._disk.pickle_protocol == 0

        cache.reset('disk_min_file_size', 2 ** 10)
        cache.reset('disk_pickle_protocol', 2)

        cache[1] = value
        cache.check()

        assert cache.disk_min_file_size == 2 ** 10
        assert cache.disk_pickle_protocol == 2
        assert cache._disk.min_file_size == 2 ** 10
        assert cache._disk.pickle_protocol == 2

    shutil.rmtree(cache.directory, ignore_errors=True)


def test_disk_valueerror():
    with pytest.raises(ValueError):
        with dc.Cache(disk=dc.Disk('test')):
            pass


def test_custom_disk():
    with dc.Cache(disk=dc.JSONDisk, disk_compress_level=6) as cache:
        values = [None, True, 0, 1.23, {}, [None] * 10000]

        for value in values:
            cache[value] = value

        for value in values:
            assert cache[value] == value

        for key, value in zip(cache, values):
            assert key == value

        test_memoize_iter(cache)

    shutil.rmtree(cache.directory, ignore_errors=True)


class SHA256FilenameDisk(dc.Disk):
    def filename(self, key=dc.UNKNOWN, value=dc.UNKNOWN):
        filename = hashlib.sha256(key).hexdigest()[:32]
        full_path = op.join(self._directory, filename)
        return filename, full_path


def test_custom_filename_disk():
    with dc.Cache(disk=SHA256FilenameDisk) as cache:
        for count in range(100, 200):
            key = str(count).encode('ascii')
            cache[key] = str(count) * int(1e5)

    for count in range(100, 200):
        key = str(count).encode('ascii')
        filename = hashlib.sha256(key).hexdigest()[:32]
        full_path = op.join(cache.directory, filename)

        with open(full_path) as reader:
            content = reader.read()
            assert content == str(count) * int(1e5)

    shutil.rmtree(cache.directory, ignore_errors=True)


def test_init_makedirs():
    cache_dir = tempfile.mkdtemp()
    shutil.rmtree(cache_dir)
    makedirs = mock.Mock(side_effect=OSError(errno.EACCES))

    with pytest.raises(EnvironmentError):
        try:
            with mock.patch('os.makedirs', makedirs):
                dc.Cache(cache_dir)
        except EnvironmentError:
            shutil.rmtree(cache_dir, ignore_errors=True)
            raise


def test_pragma_error(cache):
    local = mock.Mock()
    con = mock.Mock()
    execute = mock.Mock()
    cursor = mock.Mock()
    fetchall = mock.Mock()

    local.pid = os.getpid()
    local.con = con
    con.execute = execute
    execute.return_value = cursor
    cursor.fetchall = fetchall
    fetchall.side_effect = [sqlite3.OperationalError] * 60000

    size = 2 ** 28

    with mock.patch('time.sleep', lambda num: 0):
        with mock.patch.object(cache, '_local', local):
            with pytest.raises(sqlite3.OperationalError):
                cache.reset('sqlite_mmap_size', size)


def test_close_error(cache):
    class LocalTest(object):
        def __init__(self):
            self._calls = 0

        def __getattr__(self, name):
            if self._calls:
                raise AttributeError
            else:
                self._calls += 1
                return mock.Mock()

    with mock.patch.object(cache, '_local', LocalTest()):
        cache.close()


def test_getsetdel(cache):
    values = [
        (None, False),
        ((None,) * 2 ** 20, False),
        (1234, False),
        (2 ** 512, False),
        (56.78, False),
        (u'hello', False),
        (u'hello' * 2 ** 20, False),
        (b'world', False),
        (b'world' * 2 ** 20, False),
        (io.BytesIO(b'world' * 2 ** 20), True),
    ]

    for key, (value, file_like) in enumerate(values):
        assert cache.set(key, value, read=file_like)

    assert len(cache) == len(values)

    for key, (value, file_like) in enumerate(values):
        if file_like:
            assert cache[key] == value.getvalue()
        else:
            assert cache[key] == value

    for key, _ in enumerate(values):
        del cache[key]

    assert len(cache) == 0

    for value, (key, _) in enumerate(values):
        cache[key] = value

    assert len(cache) == len(values)

    for value, (key, _) in enumerate(values):
        assert cache[key] == value

    for _, (key, _) in enumerate(values):
        del cache[key]

    assert len(cache) == 0

    cache.check()


def test_get_keyerror1(cache):
    with pytest.raises(KeyError):
        cache[0]


def test_get_keyerror4(cache):
    func = mock.Mock(side_effect=IOError(errno.ENOENT, ''))

    cache.reset('statistics', True)
    cache[0] = b'abcd' * 2 ** 20

    with mock.patch('diskcache.core.open', func):
        with pytest.raises((IOError, KeyError, OSError)):
            cache[0]


def test_read(cache):
    cache.set(0, b'abcd' * 2 ** 20)
    with cache.read(0) as reader:
        assert reader is not None


def test_read_keyerror(cache):
    with pytest.raises(KeyError):
        with cache.read(0):
            pass


def test_set_twice(cache):
    large_value = b'abcd' * 2 ** 20

    cache[0] = 0
    cache[0] = 1

    assert cache[0] == 1

    cache[0] = large_value

    assert cache[0] == large_value
    with cache.get(0, read=True) as reader:
        assert reader.name is not None

    cache[0] = 2

    assert cache[0] == 2
    assert cache.get(0, read=True) == 2

    cache.check()


def test_set_timeout(cache):
    local = mock.Mock()
    con = mock.Mock()
    execute = mock.Mock()

    local.pid = os.getpid()
    local.con = con
    con.execute = execute
    execute.side_effect = sqlite3.OperationalError

    with pytest.raises(dc.Timeout):
        try:
            with mock.patch.object(cache, '_local', local):
                cache.set('a', 'b' * 2 ** 20)
        finally:
            cache.check()


def test_raw(cache):
    assert cache.set(0, io.BytesIO(b'abcd'), read=True)
    assert cache[0] == b'abcd'


def test_get(cache):
    assert cache.get(0) is None
    assert cache.get(1, 'dne') == 'dne'
    assert cache.get(2, {}) == {}
    assert cache.get(0, expire_time=True, tag=True) == (None, None, None)

    assert cache.set(0, 0, expire=None, tag=u'number')

    assert cache.get(0, expire_time=True) == (0, None)
    assert cache.get(0, tag=True) == (0, u'number')
    assert cache.get(0, expire_time=True, tag=True) == (0, None, u'number')


def test_get_expired_fast_path(cache):
    assert cache.set(0, 0, expire=0.001)
    time.sleep(0.01)
    assert cache.get(0) is None


def test_get_ioerror_fast_path(cache):
    assert cache.set(0, 0)

    disk = mock.Mock()
    put = mock.Mock()
    fetch = mock.Mock()

    disk.put = put
    put.side_effect = [(0, True)]
    disk.fetch = fetch
    io_error = IOError()
    io_error.errno = errno.ENOENT
    fetch.side_effect = io_error

    with mock.patch.object(cache, '_disk', disk):
        assert cache.get(0) is None


def test_get_expired_slow_path(cache):
    cache.stats(enable=True)
    cache.reset('eviction_policy', 'least-recently-used')
    assert cache.set(0, 0, expire=0.001)
    time.sleep(0.01)
    assert cache.get(0) is None


def test_pop(cache):
    assert cache.incr('alpha') == 1
    assert cache.pop('alpha') == 1
    assert cache.get('alpha') is None
    assert cache.check() == []

    assert cache.set('alpha', 123, expire=1, tag='blue')
    assert cache.pop('alpha', tag=True) == (123, 'blue')

    assert cache.set('beta', 456, expire=1e-9, tag='green')
    time.sleep(0.01)
    assert cache.pop('beta', 'dne') == 'dne'

    assert cache.set('gamma', 789, tag='red')
    assert cache.pop('gamma', expire_time=True, tag=True) == (789, None, 'red')

    assert cache.pop('dne') is None

    assert cache.set('delta', 210)
    assert cache.pop('delta', expire_time=True) == (210, None)

    assert cache.set('epsilon', '0' * 2 ** 20)
    assert cache.pop('epsilon') == '0' * 2 ** 20


def test_pop_ioerror(cache):
    assert cache.set(0, 0)

    disk = mock.Mock()
    put = mock.Mock()
    fetch = mock.Mock()

    disk.put = put
    put.side_effect = [(0, True)]
    disk.fetch = fetch
    io_error = IOError()
    io_error.errno = errno.ENOENT
    fetch.side_effect = io_error

    with mock.patch.object(cache, '_disk', disk):
        assert cache.pop(0) is None


def test_delete(cache):
    cache[0] = 0
    assert cache.delete(0)
    assert len(cache) == 0
    assert not cache.delete(0)
    assert len(cache.check()) == 0


def test_del(cache):
    with pytest.raises(KeyError):
        del cache[0]


def test_del_expired(cache):
    cache.set(0, 0, expire=0.001)
    time.sleep(0.01)
    with pytest.raises(KeyError):
        del cache[0]


def test_stats(cache):
    cache[0] = 0

    assert cache.stats(enable=True) == (0, 0)

    for _ in range(100):
        cache[0]

    for _ in range(10):
        cache.get(1)

    assert cache.stats(reset=True) == (100, 10)
    assert cache.stats(enable=False) == (0, 0)

    for _ in range(100):
        cache[0]

    for _ in range(10):
        cache.get(1)

    assert cache.stats() == (0, 0)
    assert len(cache.check()) == 0


def test_path(cache):
    cache[0] = u'abc'
    large_value = b'abc' * 2 ** 20
    cache[1] = large_value

    assert cache.get(0, read=True) == u'abc'

    with cache.get(1, read=True) as reader:
        assert reader.name is not None
        path = reader.name

    with open(path, 'rb') as reader:
        value = reader.read()

    assert value == large_value

    assert len(cache.check()) == 0


def test_expire_rows(cache):
    cache.reset('cull_limit', 0)

    for value in range(10):
        assert cache.set(value, value, expire=1e-9)

    for value in range(10, 15):
        assert cache.set(value, value)

    assert len(cache) == 15

    time.sleep(0.01)
    cache.reset('cull_limit', 10)

    assert cache.set(15, 15)

    assert len(cache) == 6
    assert len(cache.check()) == 0


def test_least_recently_stored(cache):
    cache.reset('eviction_policy', u'least-recently-stored')
    cache.reset('size_limit', int(10.1e6))
    cache.reset('cull_limit', 2)

    million = b'x' * int(1e6)

    for value in range(10):
        cache[value] = million

    assert len(cache) == 10

    for value in range(10):
        assert cache[value] == million

    for value in range(10, 20):
        cache[value] = million

    assert len(cache) == 10

    for value in range(10):
        cache[value] = million

    count = len(cache)

    for index, length in enumerate([1, 2, 3, 4]):
        cache[10 + index] = million * length
        assert len(cache) == count - length

    assert cache[12] == million * 3
    assert cache[13] == million * 4

    assert len(cache.check()) == 0


def test_least_recently_used(cache):
    cache.reset('eviction_policy', u'least-recently-used')
    cache.reset('size_limit', int(10.1e6))
    cache.reset('cull_limit', 5)

    million = b'x' * int(1e6)

    for value in range(10):
        cache[value] = million

    assert len(cache) == 10

    time.sleep(0.01)

    cache[0]
    cache[1]
    cache[7]
    cache[8]
    cache[9]

    cache[10] = million

    assert len(cache) == 6

    for value in [0, 1, 7, 8, 9, 10]:
        assert cache[value] == million

    assert len(cache.check()) == 0


def test_least_frequently_used(cache):
    cache.reset('eviction_policy', u'least-frequently-used')
    cache.reset('size_limit', int(10.1e6))
    cache.reset('cull_limit', 5)

    million = b'x' * int(1e6)

    for value in range(10):
        cache[value] = million

    assert len(cache) == 10

    cache[0], cache[0], cache[0], cache[0], cache[0]
    cache[1], cache[1], cache[1], cache[1]
    cache[7], cache[7], cache[7]
    cache[8], cache[8]
    cache[9]

    cache[10] = million

    assert len(cache) == 6

    for value in [0, 1, 7, 8, 9, 10]:
        assert cache[value] == million

    assert len(cache.check()) == 0


def test_check(cache):
    blob = b'a' * 2 ** 20
    keys = (0, 1, 1234, 56.78, u'hello', b'world', None)

    for key in keys:
        cache[key] = blob

    # Cause mayhem.

    with cache.get(0, read=True) as reader:
        full_path = reader.name
    os.rename(full_path, full_path + '_moved')

    with cache.get(1, read=True) as reader:
        full_path = reader.name
    os.remove(full_path)

    cache._sql('UPDATE Cache SET size = 0 WHERE rowid > 1')
    cache.reset('count', 0)
    cache.reset('size', 0)

    with warnings.catch_warnings():
        warnings.filterwarnings('ignore')
        cache.check()
        cache.check(fix=True)

    assert len(cache.check()) == 0  # Should display no warnings.


def test_integrity_check(cache):
    for value in range(1000):
        cache[value] = value

    cache.close()

    with io.open(op.join(cache.directory, 'cache.db'), 'r+b') as writer:
        writer.seek(52)
        writer.write(b'\x00\x01')  # Should be 0, change it.

    cache = dc.Cache(cache.directory)

    with warnings.catch_warnings():
        warnings.filterwarnings('ignore')
        cache.check()
        cache.check(fix=True)

    assert len(cache.check()) == 0


def test_expire(cache):
    cache.reset('cull_limit', 0)  # Disable expiring keys on `set`.
    now = time.time()
    time_time = mock.Mock(return_value=now)

    with mock.patch('time.time', time_time):
        for value in range(1, 101):
            assert cache.set(value, value, expire=value)

    assert len(cache) == 100

    time_time = mock.Mock(return_value=now + 11)
    cache.reset('cull_limit', 10)
    with mock.patch('time.time', time_time):
        assert cache.expire() == 10

    assert len(cache) == 90
    assert len(cache.check()) == 0


def test_tag_index():
    with dc.Cache(tag_index=True) as cache:
        assert cache.tag_index == 1
    shutil.rmtree(cache.directory, ignore_errors=True)


def test_evict(cache):
    colors = ('red', 'blue', 'yellow')

    for value in range(90):
        assert cache.set(value, value, tag=colors[value % len(colors)])

    assert len(cache) == 90
    assert cache.evict('red') == 30
    assert len(cache) == 60
    assert len(cache.check()) == 0


def test_clear(cache):
    for value in range(100):
        cache[value] = value
    assert len(cache) == 100
    assert cache.clear() == 100
    assert len(cache) == 0
    assert len(cache.check()) == 0


def test_clear_timeout(cache):
    transact = mock.Mock()
    transact.side_effect = dc.Timeout
    with mock.patch.object(cache, '_transact', transact):
        with pytest.raises(dc.Timeout):
            cache.clear()


def test_tag(cache):
    assert cache.set(0, None, tag=u'zero')
    assert cache.set(1, None, tag=1234)
    assert cache.set(2, None, tag=5.67)
    assert cache.set(3, None, tag=b'three')

    assert cache.get(0, tag=True) == (None, u'zero')
    assert cache.get(1, tag=True) == (None, 1234)
    assert cache.get(2, tag=True) == (None, 5.67)
    assert cache.get(3, tag=True) == (None, b'three')


def test_with(cache):
    with dc.Cache(cache.directory) as tmp:
        tmp[u'a'] = 0
        tmp[u'b'] = 1

    assert cache[u'a'] == 0
    assert cache[u'b'] == 1


def test_contains(cache):
    assert 0 not in cache
    cache[0] = 0
    assert 0 in cache


def test_touch(cache):
    assert cache.set(0, None, expire=60)
    assert cache.touch(0, expire=None)
    assert cache.touch(0, expire=0)
    assert not cache.touch(0)


def test_add(cache):
    assert cache.add(1, 1)
    assert cache.get(1) == 1
    assert not cache.add(1, 2)
    assert cache.get(1) == 1
    assert cache.delete(1)
    assert cache.add(1, 1, expire=0.001)
    time.sleep(0.01)
    assert cache.add(1, 1)
    cache.check()


def test_add_large_value(cache):
    value = b'abcd' * 2 ** 20
    assert cache.add(b'test-key', value)
    assert cache.get(b'test-key') == value
    assert not cache.add(b'test-key', value * 2)
    assert cache.get(b'test-key') == value
    cache.check()


def test_add_timeout(cache):
    local = mock.Mock()
    con = mock.Mock()
    execute = mock.Mock()

    local.pid = os.getpid()
    local.con = con
    con.execute = execute
    execute.side_effect = sqlite3.OperationalError

    with pytest.raises(dc.Timeout):
        try:
            with mock.patch.object(cache, '_local', local):
                cache.add(0, 0)
        finally:
            cache.check()


def test_incr(cache):
    assert cache.incr('key', default=5) == 6
    assert cache.incr('key', 2) == 8
    assert cache.get('key', expire_time=True, tag=True) == (8, None, None)
    assert cache.delete('key')
    assert cache.set('key', 100, expire=0.100)
    assert cache.get('key') == 100
    time.sleep(0.120)
    assert cache.incr('key') == 1


def test_incr_insert_keyerror(cache):
    with pytest.raises(KeyError):
        cache.incr('key', default=None)


def test_incr_update_keyerror(cache):
    assert cache.set('key', 100, expire=0.100)
    assert cache.get('key') == 100
    time.sleep(0.120)
    with pytest.raises(KeyError):
        cache.incr('key', default=None)


def test_decr(cache):
    assert cache.decr('key', default=5) == 4
    assert cache.decr('key', 2) == 2
    assert cache.get('key', expire_time=True, tag=True) == (2, None, None)
    assert cache.delete('key')
    assert cache.set('key', 100, expire=0.100)
    assert cache.get('key') == 100
    time.sleep(0.120)
    assert cache.decr('key') == -1


def test_iter(cache):
    sequence = list('abcdef') + [('g',)]

    for index, value in enumerate(sequence):
        cache[value] = index

    iterator = iter(cache)

    assert all(one == two for one, two in zip(sequence, iterator))

    cache['h'] = 7

    with pytest.raises(StopIteration):
        next(iterator)


def test_iter_expire(cache):
    cache.reset('cull_limit', 0)
    for num in range(100):
        cache.set(num, num, expire=1e-9)
    assert len(cache) == 100
    assert list(cache) == list(range(100))


def test_iter_error(cache):
    with pytest.raises(StopIteration):
        next(iter(cache))


def test_reversed(cache):
    sequence = 'abcdef'

    for index, value in enumerate(sequence):
        cache[value] = index

    iterator = reversed(cache)

    pairs = zip(reversed(sequence), iterator)
    assert all(one == two for one, two in pairs)

    try:
        next(iterator)
    except StopIteration:
        pass
    else:
        assert False, 'StopIteration expected'


def test_reversed_error(cache):
    with pytest.raises(StopIteration):
        next(reversed(cache))


def test_push_pull(cache):
    for value in range(10):
        cache.push(value)

    for value in range(10):
        _, pull_value = cache.pull()
        assert pull_value == value

    assert len(cache) == 0


def test_push_pull_prefix(cache):
    for value in range(10):
        cache.push(value, prefix='key')

    for value in range(10):
        key, peek_value = cache.peek(prefix='key')
        key, pull_value = cache.pull(prefix='key')
        assert key.startswith('key')
        assert peek_value == value
        assert pull_value == value

    assert len(cache) == 0
    assert len(cache.check()) == 0


def test_push_pull_extras(cache):
    cache.push('test')
    assert cache.pull() == (500000000000000, 'test')
    assert len(cache) == 0

    cache.push('test', expire=10)
    (key, value), expire_time = cache.peek(expire_time=True)
    assert key == 500000000000000
    assert value == 'test'
    assert expire_time > time.time()
    assert len(cache) == 1
    (key, value), expire_time = cache.pull(expire_time=True)
    assert key == 500000000000000
    assert value == 'test'
    assert expire_time > time.time()
    assert len(cache) == 0

    cache.push('test', tag='foo')
    (key, value), tag = cache.peek(tag=True)
    assert key == 500000000000000
    assert value == 'test'
    assert tag == 'foo'
    assert len(cache) == 1
    (key, value), tag = cache.pull(tag=True)
    assert key == 500000000000000
    assert value == 'test'
    assert tag == 'foo'
    assert len(cache) == 0

    cache.push('test')
    (key, value), expire_time, tag = cache.peek(expire_time=True, tag=True)
    assert key == 500000000000000
    assert value == 'test'
    assert expire_time is None
    assert tag is None
    assert len(cache) == 1
    (key, value), expire_time, tag = cache.pull(expire_time=True, tag=True)
    assert key == 500000000000000
    assert value == 'test'
    assert expire_time is None
    assert tag is None
    assert len(cache) == 0

    assert cache.pull(default=(0, 1)) == (0, 1)

    assert len(cache.check()) == 0


def test_push_pull_expire(cache):
    cache.push(0, expire=0.1)
    cache.push(0, expire=0.1)
    cache.push(0, expire=0.1)
    cache.push(1)
    time.sleep(0.2)
    assert cache.pull() == (500000000000003, 1)
    assert len(cache) == 0
    assert len(cache.check()) == 0


def test_push_peek_expire(cache):
    cache.push(0, expire=0.1)
    cache.push(0, expire=0.1)
    cache.push(0, expire=0.1)
    cache.push(1)
    time.sleep(0.2)
    assert cache.peek() == (500000000000003, 1)
    assert len(cache) == 1
    assert len(cache.check()) == 0


def test_push_pull_large_value(cache):
    value = b'test' * (2 ** 20)
    cache.push(value)
    assert cache.pull() == (500000000000000, value)
    assert len(cache) == 0
    assert len(cache.check()) == 0


def test_push_peek_large_value(cache):
    value = b'test' * (2 ** 20)
    cache.push(value)
    assert cache.peek() == (500000000000000, value)
    assert len(cache) == 1
    assert len(cache.check()) == 0


def test_pull_ioerror(cache):
    assert cache.push(0) == 500000000000000

    disk = mock.Mock()
    put = mock.Mock()
    fetch = mock.Mock()

    disk.put = put
    put.side_effect = [(0, True)]
    disk.fetch = fetch
    io_error = IOError()
    io_error.errno = errno.ENOENT
    fetch.side_effect = io_error

    with mock.patch.object(cache, '_disk', disk):
        assert cache.pull() == (None, None)


def test_peek_ioerror(cache):
    assert cache.push(0) == 500000000000000

    disk = mock.Mock()
    put = mock.Mock()
    fetch = mock.Mock()

    disk.put = put
    put.side_effect = [(0, True)]
    disk.fetch = fetch
    io_error = IOError()
    io_error.errno = errno.ENOENT
    fetch.side_effect = [io_error, 0]

    with mock.patch.object(cache, '_disk', disk):
        _, value = cache.peek()
        assert value == 0


def test_peekitem_extras(cache):
    with pytest.raises(KeyError):
        cache.peekitem()

    assert cache.set('a', 0)
    assert cache.set('b', 1)
    assert cache.set('c', 2, expire=10, tag='foo')
    assert cache.set('d', 3, expire=0.1)
    assert cache.set('e', 4, expire=0.1)

    time.sleep(0.2)

    (key, value), expire_time, tag = cache.peekitem(expire_time=True, tag=True)
    assert key == 'c'
    assert value == 2
    assert expire_time > 0
    assert tag == 'foo'

    (key, value), expire_time = cache.peekitem(expire_time=True)
    assert key == 'c'
    assert value == 2
    assert expire_time > 0

    (key, value), tag = cache.peekitem(tag=True)
    assert key == 'c'
    assert value == 2
    assert expire_time > 0