openstack/swift
Code Issues Proposed changes

Make test_get_more_nodes_with_zero_weight_region more robust

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...by using a random ring, looking at *all* partitions, and making
assertions about the distribution of how many times we have to call
next().

Change-Id: Ia5feb9396d4bf6fd35f16bbc5280e63022ed2c47
This commit is contained in:
Tim Burke 2017-01-09 20:00:33 +00:00
parent bf09a06708
commit 0d4d940243
1 changed files with 36 additions and 8 deletions
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40
test/unit/common/ring/test_ring.py
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@ -14,6 +14,7 @@
# limitations under the License. # limitations under the License.
import array import array
import collections
import six.moves.cPickle as pickle import six.moves.cPickle as pickle
import os import os
import unittest import unittest
@ -23,7 +24,6 @@ from gzip import GzipFile
from tempfile import mkdtemp from tempfile import mkdtemp
from shutil import rmtree from shutil import rmtree
from time import sleep, time from time import sleep, time
import random
import sys import sys
import copy import copy
import mock import mock
@ -35,6 +35,7 @@ from swift.common.ring import utils as ring_utils
class TestRingBase(unittest.TestCase): class TestRingBase(unittest.TestCase):
longMessage = True
def setUp(self): def setUp(self):
self._orig_hash_suffix = utils.HASH_PATH_SUFFIX self._orig_hash_suffix = utils.HASH_PATH_SUFFIX
@ -874,7 +875,7 @@ class TestRing(TestRingBase):
else: else:
dev['weight'] = 1.0 dev['weight'] = 1.0
rb.add_dev(dev) rb.add_dev(dev)
rb.rebalance(seed=1) rb.rebalance()
rb.get_ring().save(self.testgz) rb.get_ring().save(self.testgz)
r = ring.Ring(self.testdir, ring_name='whatever') r = ring.Ring(self.testdir, ring_name='whatever')
@ -898,16 +899,43 @@ class TestRing(TestRingBase):
def __getitem__(self, key): def __getitem__(self, key):
return self.table[key] return self.table[key]
histogram = collections.defaultdict(int)
for part in range(r.partition_count):
counting_table = CountingRingTable(r._replica2part2dev_id) counting_table = CountingRingTable(r._replica2part2dev_id)
r._replica2part2dev_id = counting_table with mock.patch.object(r, '_replica2part2dev_id', counting_table):
part = random.randint(0, r.partition_count)
node_iter = r.get_more_nodes(part) node_iter = r.get_more_nodes(part)
next(node_iter) next(node_iter)
self.assertLess(counting_table.count, 14) histogram[counting_table.count] += 1
# Don't let our summing muddy our histogram
histogram = dict(histogram)
# sanity # sanity
self.assertEqual(1, r._num_regions) self.assertEqual(1, r._num_regions)
self.assertEqual(2, r._num_zones) self.assertEqual(2, r._num_zones)
self.assertEqual(256, r.partition_count)
# We always do one loop (including the StopIteration) while getting
# primaries, so every part should hit next() at least 5 times
self.assertEqual(sum(histogram.get(x, 0) for x in range(5)), 0,
histogram)
# Most of the parts should find a handoff device in the next partition,
# but because some of the primary devices may *also* be used for that
# partition, that means 5, 6, or 7 calls to next().
self.assertGreater(sum(histogram.get(x, 0) for x in range(8)), 160,
histogram)
# Want 90% confidence that it'll happen within two partitions
self.assertGreater(sum(histogram.get(x, 0) for x in range(12)), 230,
histogram)
# Tail should fall off fairly quickly
self.assertLess(sum(histogram.get(x, 0) for x in range(20, 100)), 5,
histogram)
# Hard limit at 50 (we've seen as bad as 41, 45)
self.assertEqual(sum(histogram.get(x, 0) for x in range(50, 100)), 0,
histogram)
if __name__ == '__main__': if __name__ == '__main__':