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tests: add test that verifier notices any (randomly chosen) bit flipped in the verifiable part of any (randomly chosen) share

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The currently verifier doesn't (usually) pass this randomized test, hence the TODO.
This commit is contained in:
Zooko O'Whielacronx 2008-07-30 17:20:15 -07:00
parent 86160c3fc9
commit 6d3ec390b0
1 changed files with 49 additions and 4 deletions
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53
src/allmydata/test/test_system.py
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@ -1,5 +1,5 @@
from base64 import b32encode
import os, random, sys, time, re, simplejson
import os, random, struct, sys, time, re, simplejson
from cStringIO import StringIO
from twisted.trial import unittest
from twisted.internet import defer
@ -1712,7 +1712,7 @@ class Checker(SystemTestMixin, unittest.TestCase):
# Set self.basedir to a temp dir which has the name of the current test method in its
# name.
self.basedir = self.mktemp()
TEST_DATA="\x02"*1000
TEST_DATA="\x02"*(upload.Uploader.URI_LIT_SIZE_THRESHOLD+1)
d = defer.maybeDeferred(SystemTestMixin.setUp, self)
d.addCallback(lambda x: self.set_up_nodes())
@ -1764,12 +1764,21 @@ class Checker(SystemTestMixin, unittest.TestCase):
open(pathtosharefile, "w").write(newdata)
def _corrupt_a_share(self, unused=None):
""" Exactly one bit of exactly one share on disk will be flipped (randomly selected). """
""" Exactly one bit of exactly one share on disk will be flipped (randomly selected from
among the bits of the 'share data' -- the verifiable bits)."""
shares = self._find_shares()
ks = shares.keys()
k = random.choice(ks)
data = shares[k]
shares[k] = testutil.flip_one_bit(shares[k])
(version, size, num_leases) = struct.unpack(">LLL", data[:0xc])
sharedata = data[0xc:0xc+size]
corruptedsharedata = testutil.flip_one_bit(sharedata)
corrupteddata = data[:0xc]+corruptedsharedata+data[0xc+size:]
shares[k] = corrupteddata
self._replace_shares(shares)
def test_test_code(self):
@ -1855,3 +1864,39 @@ class Checker(SystemTestMixin, unittest.TestCase):
d.addCallback(_check3)
return d
def test_check_with_verify(self):
""" Check says the file is healthy when none of the shares have been touched. It says
that the file is unhealthy if one bit of one share has been flipped."""
DELTA_READS = 10 * 2 # N == 10
d = defer.succeed(self.filenode)
def _check1(filenode):
before_check_reads = self._count_reads()
d2 = filenode.check(verify=True, repair=False)
def _after_check(checkresults):
after_check_reads = self._count_reads()
# print "delta was ", after_check_reads - before_check_reads
self.failIf(after_check_reads - before_check_reads > DELTA_READS)
self.failUnless(checkresults.is_healthy())
d2.addCallback(_after_check)
return d2
d.addCallback(_check1)
d.addCallback(self._corrupt_a_share)
def _check2(ignored):
before_check_reads = self._count_reads()
d2 = self.filenode.check(verify=True, repair=False)
def _after_check(checkresults):
after_check_reads = self._count_reads()
# print "delta was ", after_check_reads - before_check_reads
self.failIf(after_check_reads - before_check_reads > DELTA_READS)
self.failIf(checkresults.is_healthy())
d2.addCallback(_after_check)
return d2
d.addCallback(_check2)
return d
test_check_with_verify.todo = "We haven't implemented a verifier this thorough yet."