test_pickle.py

# pylint: disable=E1101,E1103,W0232

"""
manage legacy pickle tests

How to add pickle tests:

1. Install pandas version intended to output the pickle.

2. Execute "generate_legacy_storage_files.py" to create the pickle.
$ python generate_legacy_storage_files.py <output_dir> pickle

3. Move the created pickle to "data/legacy_pickle/<version>" directory.
"""
from distutils.version import LooseVersion
import glob
import os
import shutil
from warnings import catch_warnings, simplefilter

import pytest

from pandas.compat import PY3, is_platform_little_endian
import pandas.util._test_decorators as td

import pandas as pd
from pandas import Index
import pandas.util.testing as tm

from pandas.tseries.offsets import Day, MonthEnd


@pytest.fixture(scope='module')
def current_pickle_data():
    # our current version pickle data
    from pandas.tests.io.generate_legacy_storage_files import (
        create_pickle_data)
    return create_pickle_data()


# ---------------------
# comparison functions
# ---------------------
def compare_element(result, expected, typ, version=None):
    if isinstance(expected, Index):
        tm.assert_index_equal(expected, result)
        return

    if typ.startswith('sp_'):
        comparator = getattr(tm, "assert_%s_equal" % typ)
        comparator(result, expected, exact_indices=False)
    elif typ == 'timestamp':
        if expected is pd.NaT:
            assert result is pd.NaT
        else:
            assert result == expected
            assert result.freq == expected.freq
    else:
        comparator = getattr(tm, "assert_%s_equal" %
                             typ, tm.assert_almost_equal)
        comparator(result, expected)


def compare(data, vf, version):

    # py3 compat when reading py2 pickle
    try:
        data = pd.read_pickle(vf)
    except (ValueError) as e:
        if 'unsupported pickle protocol:' in str(e):
            # trying to read a py3 pickle in py2
            return
        else:
            raise

    m = globals()
    for typ, dv in data.items():
        for dt, result in dv.items():
            try:
                expected = data[typ][dt]
            except (KeyError):
                if version in ('0.10.1', '0.11.0') and dt == 'reg':
                    break
                else:
                    raise

            # use a specific comparator
            # if available
            comparator = "compare_{typ}_{dt}".format(typ=typ, dt=dt)

            comparator = m.get(comparator, m['compare_element'])
            comparator(result, expected, typ, version)
    return data


def compare_sp_series_ts(res, exp, typ, version):
    # SparseTimeSeries integrated into SparseSeries in 0.12.0
    # and deprecated in 0.17.0
    if version and LooseVersion(version) <= LooseVersion("0.12.0"):
        tm.assert_sp_series_equal(res, exp, check_series_type=False)
    else:
        tm.assert_sp_series_equal(res, exp)


def compare_series_ts(result, expected, typ, version):
    # GH 7748
    tm.assert_series_equal(result, expected)
    assert result.index.freq == expected.index.freq
    assert not result.index.freq.normalize
    tm.assert_series_equal(result > 0, expected > 0)

    # GH 9291
    freq = result.index.freq
    assert freq + Day(1) == Day(2)

    res = freq + pd.Timedelta(hours=1)
    assert isinstance(res, pd.Timedelta)
    assert res == pd.Timedelta(days=1, hours=1)

    res = freq + pd.Timedelta(nanoseconds=1)
    assert isinstance(res, pd.Timedelta)
    assert res == pd.Timedelta(days=1, nanoseconds=1)


def compare_series_dt_tz(result, expected, typ, version):
    # 8260
    # dtype is object < 0.17.0
    if LooseVersion(version) < LooseVersion('0.17.0'):
        expected = expected.astype(object)
        tm.assert_series_equal(result, expected)
    else:
        tm.assert_series_equal(result, expected)


def compare_series_cat(result, expected, typ, version):
    # Categorical dtype is added in 0.15.0
    # ordered is changed in 0.16.0
    if LooseVersion(version) < LooseVersion('0.15.0'):
        tm.assert_series_equal(result, expected, check_dtype=False,
                               check_categorical=False)
    elif LooseVersion(version) < LooseVersion('0.16.0'):
        tm.assert_series_equal(result, expected, check_categorical=False)
    else:
        tm.assert_series_equal(result, expected)


def compare_frame_dt_mixed_tzs(result, expected, typ, version):
    # 8260
    # dtype is object < 0.17.0
    if LooseVersion(version) < LooseVersion('0.17.0'):
        expected = expected.astype(object)
        tm.assert_frame_equal(result, expected)
    else:
        tm.assert_frame_equal(result, expected)


def compare_frame_cat_onecol(result, expected, typ, version):
    # Categorical dtype is added in 0.15.0
    # ordered is changed in 0.16.0
    if LooseVersion(version) < LooseVersion('0.15.0'):
        tm.assert_frame_equal(result, expected, check_dtype=False,
                              check_categorical=False)
    elif LooseVersion(version) < LooseVersion('0.16.0'):
        tm.assert_frame_equal(result, expected, check_categorical=False)
    else:
        tm.assert_frame_equal(result, expected)


def compare_frame_cat_and_float(result, expected, typ, version):
    compare_frame_cat_onecol(result, expected, typ, version)


def compare_index_period(result, expected, typ, version):
    tm.assert_index_equal(result, expected)
    assert isinstance(result.freq, MonthEnd)
    assert result.freq == MonthEnd()
    assert result.freqstr == 'M'
    tm.assert_index_equal(result.shift(2), expected.shift(2))


def compare_sp_frame_float(result, expected, typ, version):
    if LooseVersion(version) <= LooseVersion('0.18.1'):
        tm.assert_sp_frame_equal(result, expected, exact_indices=False,
                                 check_dtype=False)
    else:
        tm.assert_sp_frame_equal(result, expected)


files = glob.glob(os.path.join(os.path.dirname(__file__), "data",
                  "legacy_pickle", "*", "*.pickle"))


@pytest.fixture(params=files)
def legacy_pickle(request, datapath):
    return datapath(request.param)


# ---------------------
# tests
# ---------------------
def test_pickles(current_pickle_data, legacy_pickle):
    if not is_platform_little_endian():
        pytest.skip("known failure on non-little endian")

    version = os.path.basename(os.path.dirname(legacy_pickle))
    with catch_warnings(record=True):
        simplefilter("ignore")
        compare(current_pickle_data, legacy_pickle, version)


def test_round_trip_current(current_pickle_data):

    try:
        import cPickle as c_pickle

        def c_pickler(obj, path):
            with open(path, 'wb') as fh:
                c_pickle.dump(obj, fh, protocol=-1)

        def c_unpickler(path):
            with open(path, 'rb') as fh:
                fh.seek(0)
                return c_pickle.load(fh)
    except ImportError:
        c_pickler = None
        c_unpickler = None

    import pickle as python_pickle

    def python_pickler(obj, path):
        with open(path, 'wb') as fh:
            python_pickle.dump(obj, fh, protocol=-1)

    def python_unpickler(path):
        with open(path, 'rb') as fh:
            fh.seek(0)
            return python_pickle.load(fh)

    data = current_pickle_data
    for typ, dv in data.items():
        for dt, expected in dv.items():

            for writer in [pd.to_pickle, c_pickler, python_pickler]:
                if writer is None:
                    continue

                with tm.ensure_clean() as path:

                    # test writing with each pickler
                    writer(expected, path)

                    # test reading with each unpickler
                    result = pd.read_pickle(path)
                    compare_element(result, expected, typ)

                    if c_unpickler is not None:
                        result = c_unpickler(path)
                        compare_element(result, expected, typ)

                    result = python_unpickler(path)
                    compare_element(result, expected, typ)


def test_pickle_v0_14_1(datapath):

    cat = pd.Categorical(values=['a', 'b', 'c'], ordered=False,
                         categories=['a', 'b', 'c', 'd'])
    pickle_path = datapath('io', 'data', 'categorical_0_14_1.pickle')
    # This code was executed once on v0.14.1 to generate the pickle:
    #
    # cat = Categorical(labels=np.arange(3), levels=['a', 'b', 'c', 'd'],
    #                   name='foobar')
    # with open(pickle_path, 'wb') as f: pickle.dump(cat, f)
    #
    tm.assert_categorical_equal(cat, pd.read_pickle(pickle_path))


def test_pickle_v0_15_2(datapath):
    # ordered -> _ordered
    # GH 9347

    cat = pd.Categorical(values=['a', 'b', 'c'], ordered=False,
                         categories=['a', 'b', 'c', 'd'])
    pickle_path = datapath('io', 'data', 'categorical_0_15_2.pickle')
    # This code was executed once on v0.15.2 to generate the pickle:
    #
    # cat = Categorical(labels=np.arange(3), levels=['a', 'b', 'c', 'd'],
    #                   name='foobar')
    # with open(pickle_path, 'wb') as f: pickle.dump(cat, f)
    #
    tm.assert_categorical_equal(cat, pd.read_pickle(pickle_path))


def test_pickle_path_pathlib():
    df = tm.makeDataFrame()
    result = tm.round_trip_pathlib(df.to_pickle, pd.read_pickle)
    tm.assert_frame_equal(df, result)


def test_pickle_path_localpath():
    df = tm.makeDataFrame()
    result = tm.round_trip_localpath(df.to_pickle, pd.read_pickle)
    tm.assert_frame_equal(df, result)


# ---------------------
# test pickle compression
# ---------------------

@pytest.fixture
def get_random_path():
    return u'__%s__.pickle' % tm.rands(10)


class TestCompression(object):

    _compression_to_extension = {
        None: ".none",
        'gzip': '.gz',
        'bz2': '.bz2',
        'zip': '.zip',
        'xz': '.xz',
    }

    def compress_file(self, src_path, dest_path, compression):
        if compression is None:
            shutil.copyfile(src_path, dest_path)
            return

        if compression == 'gzip':
            import gzip
            f = gzip.open(dest_path, "w")
        elif compression == 'bz2':
            import bz2
            f = bz2.BZ2File(dest_path, "w")
        elif compression == 'zip':
            import zipfile
            with zipfile.ZipFile(dest_path, "w",
                                 compression=zipfile.ZIP_DEFLATED) as f:
                f.write(src_path, os.path.basename(src_path))
        elif compression == 'xz':
            lzma = pd.compat.import_lzma()
            f = lzma.LZMAFile(dest_path, "w")
        else:
            msg = 'Unrecognized compression type: {}'.format(compression)
            raise ValueError(msg)

        if compression != "zip":
            with open(src_path, "rb") as fh, f:
                f.write(fh.read())

    def test_write_explicit(self, compression, get_random_path):
        base = get_random_path
        path1 = base + ".compressed"
        path2 = base + ".raw"

        with tm.ensure_clean(path1) as p1, tm.ensure_clean(path2) as p2:
            df = tm.makeDataFrame()

            # write to compressed file
            df.to_pickle(p1, compression=compression)

            # decompress
            with tm.decompress_file(p1, compression=compression) as f:
                with open(p2, "wb") as fh:
                    fh.write(f.read())

            # read decompressed file
            df2 = pd.read_pickle(p2, compression=None)

            tm.assert_frame_equal(df, df2)

    @pytest.mark.parametrize('compression', ['', 'None', 'bad', '7z'])
    def test_write_explicit_bad(self, compression, get_random_path):
        with pytest.raises(ValueError, match="Unrecognized compression type"):
            with tm.ensure_clean(get_random_path) as path:
                df = tm.makeDataFrame()
                df.to_pickle(path, compression=compression)

    @pytest.mark.parametrize('ext', [
        '', '.gz', '.bz2', '.no_compress',
        pytest.param('.xz', marks=td.skip_if_no_lzma)
    ])
    def test_write_infer(self, ext, get_random_path):
        base = get_random_path
        path1 = base + ext
        path2 = base + ".raw"
        compression = None
        for c in self._compression_to_extension:
            if self._compression_to_extension[c] == ext:
                compression = c
                break

        with tm.ensure_clean(path1) as p1, tm.ensure_clean(path2) as p2:
            df = tm.makeDataFrame()

            # write to compressed file by inferred compression method
            df.to_pickle(p1)

            # decompress
            with tm.decompress_file(p1, compression=compression) as f:
                with open(p2, "wb") as fh:
                    fh.write(f.read())

            # read decompressed file
            df2 = pd.read_pickle(p2, compression=None)

            tm.assert_frame_equal(df, df2)

    def test_read_explicit(self, compression, get_random_path):
        base = get_random_path
        path1 = base + ".raw"
        path2 = base + ".compressed"

        with tm.ensure_clean(path1) as p1, tm.ensure_clean(path2) as p2:
            df = tm.makeDataFrame()

            # write to uncompressed file
            df.to_pickle(p1, compression=None)

            # compress
            self.compress_file(p1, p2, compression=compression)

            # read compressed file
            df2 = pd.read_pickle(p2, compression=compression)

            tm.assert_frame_equal(df, df2)

    @pytest.mark.parametrize('ext', [
        '', '.gz', '.bz2', '.zip', '.no_compress',
        pytest.param('.xz', marks=td.skip_if_no_lzma)
    ])
    def test_read_infer(self, ext, get_random_path):
        base = get_random_path
        path1 = base + ".raw"
        path2 = base + ext
        compression = None
        for c in self._compression_to_extension:
            if self._compression_to_extension[c] == ext:
                compression = c
                break

        with tm.ensure_clean(path1) as p1, tm.ensure_clean(path2) as p2:
            df = tm.makeDataFrame()

            # write to uncompressed file
            df.to_pickle(p1, compression=None)

            # compress
            self.compress_file(p1, p2, compression=compression)

            # read compressed file by inferred compression method
            df2 = pd.read_pickle(p2)

            tm.assert_frame_equal(df, df2)


# ---------------------
# test pickle compression
# ---------------------

class TestProtocol(object):

    @pytest.mark.parametrize('protocol', [-1, 0, 1, 2])
    def test_read(self, protocol, get_random_path):
        with tm.ensure_clean(get_random_path) as path:
            df = tm.makeDataFrame()
            df.to_pickle(path, protocol=protocol)
            df2 = pd.read_pickle(path)
            tm.assert_frame_equal(df, df2)

    @pytest.mark.parametrize('protocol', [3, 4])
    @pytest.mark.skipif(PY3, reason="Testing invalid parameters for Python 2")
    def test_read_bad_versions(self, protocol, get_random_path):
        # For Python 2, HIGHEST_PROTOCOL should be 2.
        msg = ("pickle protocol {protocol} asked for; the highest available "
               "protocol is 2").format(protocol=protocol)
        with pytest.raises(ValueError, match=msg):
            with tm.ensure_clean(get_random_path) as path:
                df = tm.makeDataFrame()
                df.to_pickle(path, protocol=protocol)