sapling/contrib/bdiff-torture.py
Matt Mackall 01fb35972f bdiff: fix latent normalization bug
This bug is hidden by the current bias towards matches at the
beginning of the file. When this bias is tweaked later to address
recursion balancing, the normalization code could cause the next block
to shrink to a negative length, thus creating invalid delta chunks. We
add checks here to disallow that.

This bug requires test cases that are an awkwardly large size for the test
suite, but is very rapidly picked up by the included torture tester.
2016-04-21 21:53:18 -05:00

99 lines
2.1 KiB
Python

# Randomized torture test generation for bdiff
from __future__ import absolute_import, print_function
import random, sys
from mercurial import (
bdiff,
mpatch,
)
def reducetest(a, b):
tries = 0
reductions = 0
print("reducing...")
while tries < 1000:
a2 = "\n".join(l for l in a.splitlines()
if random.randint(0, 100) > 0) + "\n"
b2 = "\n".join(l for l in b.splitlines()
if random.randint(0, 100) > 0) + "\n"
if a2 == a and b2 == b:
continue
if a2 == b2:
continue
tries += 1
try:
test1(a, b)
except Exception as inst:
reductions += 1
tries = 0
a = a2
b = b2
print("reduced:", reductions, len(a) + len(b),
repr(a), repr(b))
try:
test1(a, b)
except Exception as inst:
print("failed:", inst)
sys.exit(0)
def test1(a, b):
d = bdiff.bdiff(a, b)
if not d:
raise ValueError("empty")
c = mpatch.patches(a, [d])
if c != b:
raise ValueError("bad")
def testwrap(a, b):
try:
test1(a, b)
return
except Exception as inst:
pass
print("exception:", inst)
reducetest(a, b)
def test(a, b):
testwrap(a, b)
testwrap(b, a)
def rndtest(size, noise):
a = []
src = " aaaaaaaabbbbccd"
for x in xrange(size):
a.append(src[random.randint(0, len(src) - 1)])
while True:
b = [c for c in a if random.randint(0, 99) > noise]
b2 = []
for c in b:
b2.append(c)
while random.randint(0, 99) < noise:
b2.append(src[random.randint(0, len(src) - 1)])
if b2 != a:
break
a = "\n".join(a) + "\n"
b = "\n".join(b2) + "\n"
test(a, b)
maxvol = 10000
startsize = 2
while True:
size = startsize
count = 0
while size < maxvol:
print(size)
volume = 0
while volume < maxvol:
rndtest(size, 2)
volume += size
count += 2
size *= 2
maxvol *= 4
startsize *= 4