from mako.util import LRUCache
import string, unittest, time, random
import thread
class item:
def __init__(self, id):
self.id = id
def __str__(self):
return "item id %d" % self.id
class LRUTest(unittest.TestCase):
def testlru(self):
l = LRUCache(10, threshold=.2)
for id in range(1,20):
l[id] = item(id)
# first couple of items should be gone
self.assert_(not l.has_key(1))
self.assert_(not l.has_key(2))
# next batch over the threshold of 10 should be present
for id in range(11,20):
self.assert_(l.has_key(id))
l[12]
l[15]
l[23] = item(23)
l[24] = item(24)
l[25] = item(25)
l[26] = item(26)
l[27] = item(27)
self.assert_(not l.has_key(11))
self.assert_(not l.has_key(13))
for id in (25, 24, 23, 14, 12, 19, 18, 17, 16, 15):
self.assert_(l.has_key(id))
def _disabled_test_threaded(self):
size = 100
threshold = .5
all_elems = 2000
hot_zone = range(30,40)
cache = LRUCache(size, threshold)
# element to store
class Element(object):
def __init__(self, id):
self.id = id
self.regets = 0
# return an element. we will favor ids in the relatively small
# "hot zone" 25% of the time.
def get_elem():
if random.randint(1,4) == 1:
return hot_zone[random.randint(0, len(hot_zone) - 1)]
else:
return random.randint(1, all_elems)
total = [0]
# request thread.
def request_elem():
while True:
total[0] += 1
id = get_elem()
try:
elem = cache[id]
elem.regets += 1
except KeyError:
e = Element(id)
cache[id] = e
time.sleep(random.random() / 1000)
for x in range(0,20):
thread.start_new_thread(request_elem, ())
# assert size doesn't grow unbounded, doesnt shrink well below size
for x in range(0,5):
time.sleep(1)
print "size:", len(cache)
assert len(cache) < size + size * threshold * 2
assert len(cache) > size - (size * .1)
# computs the average number of times a range of elements were "reused",
# i.e. without being removed from the cache.
def average_regets_in_range(start, end):
elem = [e for e in cache.values() if e.id >= start and e.id <= end]
if len(elem) == 0:
return 0
avg = sum([e.regets for e in elem]) / len(elem)
return avg
hotzone_avg = average_regets_in_range(30, 40)
control_avg = average_regets_in_range(450,760)
total_avg = average_regets_in_range(0, 2000)
# hotzone should be way above the others
print "total fetches", total[0], "hotzone", \
hotzone_avg, "control", \
control_avg, "total", total_avg
assert hotzone_avg > total_avg * 5 > control_avg * 5
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