def test_init():
cms = CountMinSketch(2, 4)
with pytest.raises(ValueError) as excinfo:
cms = CountMinSketch(0, 5)
assert str(excinfo.value) == 'At least one counter array is required'
with pytest.raises(ValueError) as excinfo:
cms = CountMinSketch(5, 0)
assert str(excinfo.value) == (
'The length of the counter array cannot be less then 1')
def test_create_from_expected_error():
cms = CountMinSketch.create_from_expected_error(0.000001, 0.01)
assert repr(cms) == "<CountMinSketch (5 x 2718282)>"
assert len(cms) == 13591410, 'Unexpected length'
assert cms.sizeof() == 54365640, 'Unexpected size in bytes'
with pytest.raises(ValueError) as excinfo:
cms = CountMinSketch.create_from_expected_error(0.001, 2)
assert str(excinfo.value) == 'Error rate shell be in (0, 1)'
with pytest.raises(ValueError) as excinfo:
cs = CountMinSketch.create_from_expected_error(0.0000000000001, 0.02)
assert str(excinfo.value) == 'Deviation is too small. Not enough counters'
21,
9,
29,
6,
5,
2,
3,
1,
16,
17,
15,
5,
3,
6,
9,
12,
]
if __name__ == '__main__':
cms = CountMinSketch(4, 100)
print(cms)
print("CMS uses {} bytes in the memory".format(cms.sizeof()))
for digit in DATASET:
cms.add(digit)
for digit in sorted(set(DATASET)):
print("Element: {}. Freq.: {}, Est. Freq.: {}".format(
digit, DATASET.count(digit), cms.frequency(digit)))
def test_len():
cms = CountMinSketch(2, 4)
assert len(cms) == 8
def test_frequency():
cms = CountMinSketch(4, 100)
cms.add("test")
assert cms.frequency("test") == 1, "Can't find recently added element"
assert cms.frequency("test_test") == 0, "False positive detected"
def test_add():
cms = CountMinSketch(4, 100)
for word in ["test", 1, {"hello": "world"}]:
cms.add(word)
assert cms.frequency(word) == 1, "Can't find frequency for element"
def test_repr():
cms = CountMinSketch(2, 4)
assert repr(cms) == "<CountMinSketch (2 x 4)>"
cms = CountMinSketch.create_from_expected_error(0.1, 0.01)
assert repr(cms) == "<CountMinSketch (5 x 28)>"
def test_size():
cms = CountMinSketch(2, 4)
element_size = array.array('I', [1]).itemsize
assert cms.sizeof() == element_size * len(cms), "Unexpected size in bytes"