def test_add_item(self, item, bit_array_size, nb_salt):
bloom_filter = BloomFilter(
bit_array_size=bit_array_size,
nb_salt=nb_salt
)
for salt in range(nb_salt):
custom_address = hash(''.join([str(salt), str(item)])) % bit_array_size
assert bloom_filter.bit_array[custom_address] is False
bloom_filter.add_item(item=item)
for salt in range(nb_salt):
custom_address = hash(''.join([str(salt), str(item)])) % bit_array_size
assert bloom_filter.bit_array[custom_address]
def test_all_bits_should_be_set_to_false(self, bit_array_size, nb_salt):
bloom_filter = BloomFilter(
bit_array_size=bit_array_size,
nb_salt=nb_salt
)
for bit in bloom_filter.bit_array:
assert bit is False
def test_bit_array_size(self, bit_array_size, nb_salt):
bloom_filter = BloomFilter(
bit_array_size=bit_array_size,
nb_salt=nb_salt
)
assert len(bloom_filter.bit_array) == bit_array_size
assert bloom_filter.bit_array_size == bit_array_size
def benchmark(bit_array_size, nb_salt, input_cardinal):
logger = logging.getLogger(__name__)
bloom_filter = BloomFilter(bit_array_size=bit_array_size, nb_salt=nb_salt)
for item in range(input_cardinal):
bloom_filter.add_item(item=item)
false_negative_count = 0
for item in range(input_cardinal):
if not bloom_filter.retrieve_item(item=item):
false_negative_count += 1
exp_false_negative_rate = false_negative_count / input_cardinal
the_false_negative_rate = 0
logger.info(f'False negative rate: {exp_false_negative_rate} '
f'should be {the_false_negative_rate}')
assert exp_false_negative_rate == 0
false_positive_count = 0
for item in range(input_cardinal, 101 * input_cardinal):
if bloom_filter.retrieve_item(item=item):
false_positive_count += 1
exp_false_positive_rate = false_positive_count / (100 * input_cardinal)
the_false_positive_rate = false_positive_rate(
bit_array_size=bit_array_size,
nb_salt=nb_salt,
input_cardinal=input_cardinal)
logger.info(f'False positive rate: {exp_false_positive_rate}'
f'should be >= {the_false_positive_rate} ')
assert exp_false_positive_rate <= the_false_positive_rate
return exp_false_negative_rate, exp_false_positive_rate
def test_inserted_element(self):
bf = BloomFilter(1000, 2)
bf.add('test')
bf.add('another')
assert 'test' in bf
assert 'another' in bf
def test_retrieve_item(self, item, bit_array_size, nb_salt):
bloom_filter = BloomFilter(
bit_array_size=bit_array_size,
nb_salt=nb_salt
)
assert bloom_filter.retrieve_item(item=item) is False
bloom_filter.add_item(item=item)
assert bloom_filter.retrieve_item(item=item)
def test_bloom_filter():
bloom_filter = BloomFilter(100)
bloom_filter.add("10.17.2013")
bloom_filter.add("10.17.2014")
assert not bloom_filter.not_exist("10.17.2013")
assert not bloom_filter.not_exist("10.17.2014")
assert bloom_filter.not_exist("10.17.2021")
def test_minimal_memory_error_rate(self, input_cardinal, error_rate):
bloom_filter = BloomFilter.minimal_memory_bloom_filter(
input_cardinal=input_cardinal, error_rate=error_rate)
observed_error_rate = false_positive_rate(
bit_array_size=bloom_filter.bit_array_size,
nb_salt=bloom_filter.nb_salt,
input_cardinal=input_cardinal
)
assert observed_error_rate == pytest.approx(
expected=error_rate,
abs=error_rate / 20 # 5% interval
), "Observed error rate {observed} is higher than expected {expected}".format(
observed=observed_error_rate,
expected=error_rate
)
def test_minimal_false_positive_rate(self, bit_array_size, input_cardinal):
bloom_filter = BloomFilter.minimal_false_positive_rate_bloom_filter(
bit_array_size=bit_array_size,
input_cardinal=input_cardinal
)
assert false_positive_rate(
bit_array_size=bit_array_size,
nb_salt=bloom_filter.nb_salt,
input_cardinal=input_cardinal
) < false_positive_rate(
bit_array_size=bit_array_size,
nb_salt=bloom_filter.nb_salt - 1,
input_cardinal=input_cardinal
)
assert false_positive_rate(
bit_array_size=bit_array_size,
nb_salt=bloom_filter.nb_salt,
input_cardinal=input_cardinal
) < false_positive_rate(
bit_array_size=bit_array_size,
nb_salt=bloom_filter.nb_salt + 1,
input_cardinal=input_cardinal
)
def test_zero_fp(self):
with self.assertRaises(ValueError):
bf = BloomFilter.build_for_target_fp(10000, 2.0)
def test_inserted_element_build_with_target_fp(self):
bf = BloomFilter.build_for_target_fp(10000, .01)
bf.add('word')
assert 'some_other_word' not in bf
def test_inserteds_element_build_with_target_fp(self):
bf = BloomFilter.build_for_target_fp(1000, .01)
bf.add('word')
assert 'word' in bf