borg/src/borg/testsuite/chunker_slow.py

38 lines
1.3 KiB
Python

from io import BytesIO
from .chunker import cf
from ..chunker import Chunker
from ..crypto.low_level import blake2b_256
from ..constants import * # NOQA
from ..helpers import hex_to_bin
def test_chunkpoints_unchanged():
def twist(size):
x = 1
a = bytearray(size)
for i in range(size):
x = (x * 1103515245 + 12345) & 0x7FFFFFFF
a[i] = x & 0xFF
return a
data = twist(100000)
runs = []
for winsize in (65, 129, HASH_WINDOW_SIZE, 7351):
for minexp in (4, 6, 7, 11, 12):
for maxexp in (15, 17):
if minexp >= maxexp:
continue
for maskbits in (4, 7, 10, 12):
for seed in (1849058162, 1234567653):
fh = BytesIO(data)
chunker = Chunker(seed, minexp, maxexp, maskbits, winsize)
chunks = [blake2b_256(b"", c) for c in cf(chunker.chunkify(fh, -1))]
runs.append(blake2b_256(b"", b"".join(chunks)))
# The "correct" hash below matches the existing chunker behavior.
# Future chunker optimisations must not change this, or existing repos will bloat.
overall_hash = blake2b_256(b"", b"".join(runs))
assert overall_hash == hex_to_bin("b559b0ac8df8daaa221201d018815114241ea5c6609d98913cd2246a702af4e3")