contrib/python-zstandard/tests/test_data_structures_fuzzing.py

shelve: fix crash on unshelve without .shelve metadata file

Follow up for c67c94c0e7ae and 38373da1af02.

The inline comment says "we should keep track of the unshelve node in case
we need to reuse it." Perhaps such case isn't tested, and this patch does
NOT add a test for the reuse of the unbundled revision.

Also, I have no idea what should be done if new revision is unbundled
because of "node not in repo".

import io
import os
import sys
import unittest

try:
    import hypothesis
    import hypothesis.strategies as strategies
except ImportError:
    raise unittest.SkipTest('hypothesis not available')

import zstandard as zstd

from .common import (
    make_cffi,
)


s_windowlog = strategies.integers(min_value=zstd.WINDOWLOG_MIN,
                                    max_value=zstd.WINDOWLOG_MAX)
s_chainlog = strategies.integers(min_value=zstd.CHAINLOG_MIN,
                                    max_value=zstd.CHAINLOG_MAX)
s_hashlog = strategies.integers(min_value=zstd.HASHLOG_MIN,
                                max_value=zstd.HASHLOG_MAX)
s_searchlog = strategies.integers(min_value=zstd.SEARCHLOG_MIN,
                                    max_value=zstd.SEARCHLOG_MAX)
s_searchlength = strategies.integers(min_value=zstd.SEARCHLENGTH_MIN,
                                     max_value=zstd.SEARCHLENGTH_MAX)
s_targetlength = strategies.integers(min_value=zstd.TARGETLENGTH_MIN,
                                     max_value=2**32)
s_strategy = strategies.sampled_from((zstd.STRATEGY_FAST,
                                        zstd.STRATEGY_DFAST,
                                        zstd.STRATEGY_GREEDY,
                                        zstd.STRATEGY_LAZY,
                                        zstd.STRATEGY_LAZY2,
                                        zstd.STRATEGY_BTLAZY2,
                                        zstd.STRATEGY_BTOPT,
                                        zstd.STRATEGY_BTULTRA))


@make_cffi
@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')
class TestCompressionParametersHypothesis(unittest.TestCase):
    @hypothesis.given(s_windowlog, s_chainlog, s_hashlog, s_searchlog,
                        s_searchlength, s_targetlength, s_strategy)
    def test_valid_init(self, windowlog, chainlog, hashlog, searchlog,
                        searchlength, targetlength, strategy):
        zstd.ZstdCompressionParameters(window_log=windowlog,
                                       chain_log=chainlog,
                                       hash_log=hashlog,
                                       search_log=searchlog,
                                       min_match=searchlength,
                                       target_length=targetlength,
                                       compression_strategy=strategy)

    @hypothesis.given(s_windowlog, s_chainlog, s_hashlog, s_searchlog,
                        s_searchlength, s_targetlength, s_strategy)
    def test_estimated_compression_context_size(self, windowlog, chainlog,
                                                hashlog, searchlog,
                                                searchlength, targetlength,
                                                strategy):
        if searchlength == zstd.SEARCHLENGTH_MIN and strategy in (zstd.STRATEGY_FAST, zstd.STRATEGY_GREEDY):
            searchlength += 1
        elif searchlength == zstd.SEARCHLENGTH_MAX and strategy != zstd.STRATEGY_FAST:
            searchlength -= 1

        p = zstd.ZstdCompressionParameters(window_log=windowlog,
                                           chain_log=chainlog,
                                           hash_log=hashlog,
                                           search_log=searchlog,
                                           min_match=searchlength,
                                           target_length=targetlength,
                                           compression_strategy=strategy)
        size = p.estimated_compression_context_size()