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#!/usr/bin/python
#
# Copyright 2014 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
rappor_test.py: Tests for rappor.py
"""
import cStringIO
import copy
import math
import random
import unittest
import rappor # module under test
class RapporParamsTest(unittest.TestCase):
def setUp(self):
self.typical_instance = rappor.Params()
ti = self.typical_instance # For convenience
ti.num_cohorts = 64 # Number of cohorts
ti.num_hashes = 2 # Number of bloom filter hashes
ti.num_bloombits = 16 # Number of bloom filter bits
ti.prob_p = 0.40 # Probability p
ti.prob_q = 0.70 # Probability q
ti.prob_f = 0.30 # Probability f
def testFromCsv(self):
f = cStringIO.StringIO('k,h,m,p,q,f\n32,2,64,0.5,0.75,0.6\n')
params = rappor.Params.from_csv(f)
self.assertEqual(32, params.num_bloombits)
self.assertEqual(64, params.num_cohorts)
# Malformed header
f = cStringIO.StringIO('k,h,m,p,q\n32,2,64,0.5,0.75,0.6\n')
self.assertRaises(rappor.Error, rappor.Params.from_csv, f)
# Missing second row
f = cStringIO.StringIO('k,h,m,p,q,f\n')
self.assertRaises(rappor.Error, rappor.Params.from_csv, f)
# Too many rows
f = cStringIO.StringIO('k,h,m,p,q,f\n32,2,64,0.5,0.75,0.6\nextra')
self.assertRaises(rappor.Error, rappor.Params.from_csv, f)
def testGetBloomBits(self):
for cohort in xrange(0, 64):
b = rappor.get_bloom_bits('foo', cohort, 2, 16)
#print 'cohort', cohort, 'bloom', b
def testGetPrr(self):
bloom = 1
num_bits = 8
for word in ('v1', 'v2', 'v3'):
masks = rappor.get_prr_masks('secret', word, 0.5, num_bits)
print 'masks', masks
def testToBigEndian(self):
b = rappor.to_big_endian(1)
print repr(b)
self.assertEqual(4, len(b))
def testEncoder(self):
# Test encoder with deterministic random function.
params = copy.copy(self.typical_instance)
params.prob_f = 0.5
params.prob_p = 0.5
params.prob_q = 0.75
# return these 3 probabilities in sequence.
rand = MockRandom([0.0, 0.6, 0.0], params)
e = rappor.Encoder(params, 0, 'secret', rand)
irr = e.encode("abc")
self.assertEquals(64493, irr) # given MockRandom, this is what we get
class MockRandom(object):
"""Returns one of three random values in a cyclic manner.
Mock random function that involves *some* state, as needed for tests that
call randomness several times. This makes it difficult to deal exclusively
with stubs for testing purposes.
"""
def __init__(self, cycle, params):
self.p_gen = MockRandomCall(params.prob_p, cycle, params.num_bloombits)
self.q_gen = MockRandomCall(params.prob_q, cycle, params.num_bloombits)
class MockRandomCall:
def __init__(self, prob, cycle, num_bits):
self.cycle = cycle
self.n = len(self.cycle)
self.prob = prob
self.num_bits = num_bits
def __call__(self):
counter = 0
r = 0
for i in xrange(0, self.num_bits):
rand_val = self.cycle[counter]
counter += 1
counter %= self.n # wrap around
r |= ((rand_val < self.prob) << i)
return r
if __name__ == "__main__":
unittest.main()
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