view contrib/python-zstandard/tests/test_compressor_fuzzing.py @ 43084:c2e284cee333

import-checker: allow symbol imports from mercurial.pycompat

Currently, the source transformer inserts
`from mercurial.pycompat import delattr, getattr, hasattr, setattr, open, unicode`
to the top of every file. As part of getting rid of the source transformer,
we'll need to have source code call these wrappers directly. Rather than
rewrite all call sites to call pycompat.*, I think it makes sense to import
needed symbols via explicit imports. That requires loosening the import checker
to allow this.

Differential Revision: https://phab.mercurial-scm.org/D7004

import io
import os
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,
    NonClosingBytesIO,
    random_input_data,
)


@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')
@make_cffi
class TestCompressor_stream_reader_fuzzing(unittest.TestCase):
    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_size=strategies.integers(-1, zstd.COMPRESSION_RECOMMENDED_OUTPUT_SIZE))
    def test_stream_source_read(self, original, level, source_read_size,
                                read_size):
        if read_size == 0:
            read_size = -1

        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(io.BytesIO(original), size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                chunk = reader.read(read_size)
                if not chunk:
                    break

                chunks.append(chunk)

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_size=strategies.integers(-1, zstd.COMPRESSION_RECOMMENDED_OUTPUT_SIZE))
    def test_buffer_source_read(self, original, level, source_read_size,
                                read_size):
        if read_size == 0:
            read_size = -1

        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(original, size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                chunk = reader.read(read_size)
                if not chunk:
                    break

                chunks.append(chunk)

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_sizes=strategies.data())
    def test_stream_source_read_variance(self, original, level, source_read_size,
                                         read_sizes):
        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(io.BytesIO(original), size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                read_size = read_sizes.draw(strategies.integers(-1, 16384))
                chunk = reader.read(read_size)
                if not chunk and read_size:
                    break

                chunks.append(chunk)

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_sizes=strategies.data())
    def test_buffer_source_read_variance(self, original, level, source_read_size,
                                         read_sizes):

        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(original, size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                read_size = read_sizes.draw(strategies.integers(-1, 16384))
                chunk = reader.read(read_size)
                if not chunk and read_size:
                    break

                chunks.append(chunk)

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_size=strategies.integers(1, zstd.COMPRESSION_RECOMMENDED_OUTPUT_SIZE))
    def test_stream_source_readinto(self, original, level,
                                    source_read_size, read_size):
        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(io.BytesIO(original), size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                b = bytearray(read_size)
                count = reader.readinto(b)

                if not count:
                    break

                chunks.append(bytes(b[0:count]))

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_size=strategies.integers(1, zstd.COMPRESSION_RECOMMENDED_OUTPUT_SIZE))
    def test_buffer_source_readinto(self, original, level,
                                    source_read_size, read_size):

        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(original, size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                b = bytearray(read_size)
                count = reader.readinto(b)

                if not count:
                    break

                chunks.append(bytes(b[0:count]))

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_sizes=strategies.data())
    def test_stream_source_readinto_variance(self, original, level,
                                             source_read_size, read_sizes):
        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(io.BytesIO(original), size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                read_size = read_sizes.draw(strategies.integers(1, 16384))
                b = bytearray(read_size)
                count = reader.readinto(b)

                if not count:
                    break

                chunks.append(bytes(b[0:count]))

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_sizes=strategies.data())
    def test_buffer_source_readinto_variance(self, original, level,
                                             source_read_size, read_sizes):

        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(original, size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                read_size = read_sizes.draw(strategies.integers(1, 16384))
                b = bytearray(read_size)
                count = reader.readinto(b)

                if not count:
                    break

                chunks.append(bytes(b[0:count]))

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_size=strategies.integers(-1, zstd.COMPRESSION_RECOMMENDED_OUTPUT_SIZE))
    def test_stream_source_read1(self, original, level, source_read_size,
                                 read_size):
        if read_size == 0:
            read_size = -1

        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(io.BytesIO(original), size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                chunk = reader.read1(read_size)
                if not chunk:
                    break

                chunks.append(chunk)

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_size=strategies.integers(-1, zstd.COMPRESSION_RECOMMENDED_OUTPUT_SIZE))
    def test_buffer_source_read1(self, original, level, source_read_size,
                                 read_size):
        if read_size == 0:
            read_size = -1

        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(original, size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                chunk = reader.read1(read_size)
                if not chunk:
                    break

                chunks.append(chunk)

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_sizes=strategies.data())
    def test_stream_source_read1_variance(self, original, level, source_read_size,
                                          read_sizes):
        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(io.BytesIO(original), size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                read_size = read_sizes.draw(strategies.integers(-1, 16384))
                chunk = reader.read1(read_size)
                if not chunk and read_size:
                    break

                chunks.append(chunk)

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_sizes=strategies.data())
    def test_buffer_source_read1_variance(self, original, level, source_read_size,
                                          read_sizes):

        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(original, size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                read_size = read_sizes.draw(strategies.integers(-1, 16384))
                chunk = reader.read1(read_size)
                if not chunk and read_size:
                    break

                chunks.append(chunk)

        self.assertEqual(b''.join(chunks), ref_frame)


    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_size=strategies.integers(1, zstd.COMPRESSION_RECOMMENDED_OUTPUT_SIZE))
    def test_stream_source_readinto1(self, original, level, source_read_size,
                                     read_size):
        if read_size == 0:
            read_size = -1

        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(io.BytesIO(original), size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                b = bytearray(read_size)
                count = reader.readinto1(b)

                if not count:
                    break

                chunks.append(bytes(b[0:count]))

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_size=strategies.integers(1, zstd.COMPRESSION_RECOMMENDED_OUTPUT_SIZE))
    def test_buffer_source_readinto1(self, original, level, source_read_size,
                                     read_size):
        if read_size == 0:
            read_size = -1

        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(original, size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                b = bytearray(read_size)
                count = reader.readinto1(b)

                if not count:
                    break

                chunks.append(bytes(b[0:count]))

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_sizes=strategies.data())
    def test_stream_source_readinto1_variance(self, original, level, source_read_size,
                                              read_sizes):
        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(io.BytesIO(original), size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                read_size = read_sizes.draw(strategies.integers(1, 16384))
                b = bytearray(read_size)
                count = reader.readinto1(b)

                if not count:
                    break

                chunks.append(bytes(b[0:count]))

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      source_read_size=strategies.integers(1, 16384),
                      read_sizes=strategies.data())
    def test_buffer_source_readinto1_variance(self, original, level, source_read_size,
                                              read_sizes):

        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        with cctx.stream_reader(original, size=len(original),
                                read_size=source_read_size) as reader:
            chunks = []
            while True:
                read_size = read_sizes.draw(strategies.integers(1, 16384))
                b = bytearray(read_size)
                count = reader.readinto1(b)

                if not count:
                    break

                chunks.append(bytes(b[0:count]))

        self.assertEqual(b''.join(chunks), ref_frame)



@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')
@make_cffi
class TestCompressor_stream_writer_fuzzing(unittest.TestCase):
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                        level=strategies.integers(min_value=1, max_value=5),
                        write_size=strategies.integers(min_value=1, max_value=1048576))
    def test_write_size_variance(self, original, level, write_size):
        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        b = NonClosingBytesIO()
        with cctx.stream_writer(b, size=len(original), write_size=write_size) as compressor:
            compressor.write(original)

        self.assertEqual(b.getvalue(), ref_frame)


@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')
@make_cffi
class TestCompressor_copy_stream_fuzzing(unittest.TestCase):
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      read_size=strategies.integers(min_value=1, max_value=1048576),
                      write_size=strategies.integers(min_value=1, max_value=1048576))
    def test_read_write_size_variance(self, original, level, read_size, write_size):
        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        source = io.BytesIO(original)
        dest = io.BytesIO()

        cctx.copy_stream(source, dest, size=len(original), read_size=read_size,
                         write_size=write_size)

        self.assertEqual(dest.getvalue(), ref_frame)


@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')
@make_cffi
class TestCompressor_compressobj_fuzzing(unittest.TestCase):
    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      chunk_sizes=strategies.data())
    def test_random_input_sizes(self, original, level, chunk_sizes):
        refctx = zstd.ZstdCompressor(level=level)
        ref_frame = refctx.compress(original)

        cctx = zstd.ZstdCompressor(level=level)
        cobj = cctx.compressobj(size=len(original))

        chunks = []
        i = 0
        while True:
            chunk_size = chunk_sizes.draw(strategies.integers(1, 4096))
            source = original[i:i + chunk_size]
            if not source:
                break

            chunks.append(cobj.compress(source))
            i += chunk_size

        chunks.append(cobj.flush())

        self.assertEqual(b''.join(chunks), ref_frame)

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      chunk_sizes=strategies.data(),
                      flushes=strategies.data())
    def test_flush_block(self, original, level, chunk_sizes, flushes):
        cctx = zstd.ZstdCompressor(level=level)
        cobj = cctx.compressobj()

        dctx = zstd.ZstdDecompressor()
        dobj = dctx.decompressobj()

        compressed_chunks = []
        decompressed_chunks = []
        i = 0
        while True:
            input_size = chunk_sizes.draw(strategies.integers(1, 4096))
            source = original[i:i + input_size]
            if not source:
                break

            i += input_size

            chunk = cobj.compress(source)
            compressed_chunks.append(chunk)
            decompressed_chunks.append(dobj.decompress(chunk))

            if not flushes.draw(strategies.booleans()):
                continue

            chunk = cobj.flush(zstd.COMPRESSOBJ_FLUSH_BLOCK)
            compressed_chunks.append(chunk)
            decompressed_chunks.append(dobj.decompress(chunk))

            self.assertEqual(b''.join(decompressed_chunks), original[0:i])

        chunk = cobj.flush(zstd.COMPRESSOBJ_FLUSH_FINISH)
        compressed_chunks.append(chunk)
        decompressed_chunks.append(dobj.decompress(chunk))

        self.assertEqual(dctx.decompress(b''.join(compressed_chunks),
                                         max_output_size=len(original)),
                         original)
        self.assertEqual(b''.join(decompressed_chunks), original)

@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')
@make_cffi
class TestCompressor_read_to_iter_fuzzing(unittest.TestCase):
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      read_size=strategies.integers(min_value=1, max_value=4096),
                      write_size=strategies.integers(min_value=1, max_value=4096))
    def test_read_write_size_variance(self, original, level, read_size, write_size):
        refcctx = zstd.ZstdCompressor(level=level)
        ref_frame = refcctx.compress(original)

        source = io.BytesIO(original)

        cctx = zstd.ZstdCompressor(level=level)
        chunks = list(cctx.read_to_iter(source, size=len(original),
                                        read_size=read_size,
                                        write_size=write_size))

        self.assertEqual(b''.join(chunks), ref_frame)


@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')
class TestCompressor_multi_compress_to_buffer_fuzzing(unittest.TestCase):
    @hypothesis.given(original=strategies.lists(strategies.sampled_from(random_input_data()),
                                                min_size=1, max_size=1024),
                        threads=strategies.integers(min_value=1, max_value=8),
                        use_dict=strategies.booleans())
    def test_data_equivalence(self, original, threads, use_dict):
        kwargs = {}

        # Use a content dictionary because it is cheap to create.
        if use_dict:
            kwargs['dict_data'] = zstd.ZstdCompressionDict(original[0])

        cctx = zstd.ZstdCompressor(level=1,
                                   write_checksum=True,
                                   **kwargs)

        if not hasattr(cctx, 'multi_compress_to_buffer'):
            self.skipTest('multi_compress_to_buffer not available')

        result = cctx.multi_compress_to_buffer(original, threads=-1)

        self.assertEqual(len(result), len(original))

        # The frame produced via the batch APIs may not be bit identical to that
        # produced by compress() because compression parameters are adjusted
        # from the first input in batch mode. So the only thing we can do is
        # verify the decompressed data matches the input.
        dctx = zstd.ZstdDecompressor(**kwargs)

        for i, frame in enumerate(result):
            self.assertEqual(dctx.decompress(frame), original[i])


@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')
@make_cffi
class TestCompressor_chunker_fuzzing(unittest.TestCase):
    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      chunk_size=strategies.integers(
                          min_value=1,
                          max_value=32 * 1048576),
                      input_sizes=strategies.data())
    def test_random_input_sizes(self, original, level, chunk_size, input_sizes):
        cctx = zstd.ZstdCompressor(level=level)
        chunker = cctx.chunker(chunk_size=chunk_size)

        chunks = []
        i = 0
        while True:
            input_size = input_sizes.draw(strategies.integers(1, 4096))
            source = original[i:i + input_size]
            if not source:
                break

            chunks.extend(chunker.compress(source))
            i += input_size

        chunks.extend(chunker.finish())

        dctx = zstd.ZstdDecompressor()

        self.assertEqual(dctx.decompress(b''.join(chunks),
                                         max_output_size=len(original)),
                         original)

        self.assertTrue(all(len(chunk) == chunk_size for chunk in chunks[:-1]))

    @hypothesis.settings(
        suppress_health_check=[hypothesis.HealthCheck.large_base_example])
    @hypothesis.given(original=strategies.sampled_from(random_input_data()),
                      level=strategies.integers(min_value=1, max_value=5),
                      chunk_size=strategies.integers(
                          min_value=1,
                          max_value=32 * 1048576),
                      input_sizes=strategies.data(),
                      flushes=strategies.data())
    def test_flush_block(self, original, level, chunk_size, input_sizes,
                         flushes):
        cctx = zstd.ZstdCompressor(level=level)
        chunker = cctx.chunker(chunk_size=chunk_size)

        dctx = zstd.ZstdDecompressor()
        dobj = dctx.decompressobj()

        compressed_chunks = []
        decompressed_chunks = []
        i = 0
        while True:
            input_size = input_sizes.draw(strategies.integers(1, 4096))
            source = original[i:i + input_size]
            if not source:
                break

            i += input_size

            chunks = list(chunker.compress(source))
            compressed_chunks.extend(chunks)
            decompressed_chunks.append(dobj.decompress(b''.join(chunks)))

            if not flushes.draw(strategies.booleans()):
                continue

            chunks = list(chunker.flush())
            compressed_chunks.extend(chunks)
            decompressed_chunks.append(dobj.decompress(b''.join(chunks)))

            self.assertEqual(b''.join(decompressed_chunks), original[0:i])

        chunks = list(chunker.finish())
        compressed_chunks.extend(chunks)
        decompressed_chunks.append(dobj.decompress(b''.join(chunks)))

        self.assertEqual(dctx.decompress(b''.join(compressed_chunks),
                                         max_output_size=len(original)),
                         original)
        self.assertEqual(b''.join(decompressed_chunks), original)