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aaronreidsmith / pandas   python

Repository URL to install this package:

Version: 0.25.3 

/ tests / io / test_feather.py

""" test feather-format compat """
from distutils.version import LooseVersion

import numpy as np
import pytest

import pandas as pd
import pandas.util.testing as tm
from pandas.util.testing import assert_frame_equal, ensure_clean

from pandas.io.feather_format import read_feather, to_feather  # noqa:E402

pyarrow = pytest.importorskip("pyarrow")


pyarrow_version = LooseVersion(pyarrow.__version__)


@pytest.mark.single
class TestFeather:
    def check_error_on_write(self, df, exc):
        # check that we are raising the exception
        # on writing

        with pytest.raises(exc):
            with ensure_clean() as path:
                to_feather(df, path)

    def check_round_trip(self, df, expected=None, **kwargs):

        if expected is None:
            expected = df

        with ensure_clean() as path:
            to_feather(df, path)

            result = read_feather(path, **kwargs)
            assert_frame_equal(result, expected)

    def test_error(self):

        for obj in [
            pd.Series([1, 2, 3]),
            1,
            "foo",
            pd.Timestamp("20130101"),
            np.array([1, 2, 3]),
        ]:
            self.check_error_on_write(obj, ValueError)

    def test_basic(self):

        df = pd.DataFrame(
            {
                "string": list("abc"),
                "int": list(range(1, 4)),
                "uint": np.arange(3, 6).astype("u1"),
                "float": np.arange(4.0, 7.0, dtype="float64"),
                "float_with_null": [1.0, np.nan, 3],
                "bool": [True, False, True],
                "bool_with_null": [True, np.nan, False],
                "cat": pd.Categorical(list("abc")),
                "dt": pd.date_range("20130101", periods=3),
                "dttz": pd.date_range("20130101", periods=3, tz="US/Eastern"),
                "dt_with_null": [
                    pd.Timestamp("20130101"),
                    pd.NaT,
                    pd.Timestamp("20130103"),
                ],
                "dtns": pd.date_range("20130101", periods=3, freq="ns"),
            }
        )

        assert df.dttz.dtype.tz.zone == "US/Eastern"
        self.check_round_trip(df)

    def test_duplicate_columns(self):

        # https://github.com/wesm/feather/issues/53
        # not currently able to handle duplicate columns
        df = pd.DataFrame(np.arange(12).reshape(4, 3), columns=list("aaa")).copy()
        self.check_error_on_write(df, ValueError)

    def test_stringify_columns(self):

        df = pd.DataFrame(np.arange(12).reshape(4, 3)).copy()
        self.check_error_on_write(df, ValueError)

    def test_read_columns(self):
        # GH 24025
        df = pd.DataFrame(
            {
                "col1": list("abc"),
                "col2": list(range(1, 4)),
                "col3": list("xyz"),
                "col4": list(range(4, 7)),
            }
        )
        columns = ["col1", "col3"]
        self.check_round_trip(df, expected=df[columns], columns=columns)

    def test_unsupported_other(self):

        # period
        df = pd.DataFrame({"a": pd.period_range("2013", freq="M", periods=3)})
        # Some versions raise ValueError, others raise ArrowInvalid.
        self.check_error_on_write(df, Exception)

    def test_rw_nthreads(self):
        df = pd.DataFrame({"A": np.arange(100000)})
        expected_warning = (
            "the 'nthreads' keyword is deprecated, use 'use_threads' instead"
        )
        # TODO: make the warning work with check_stacklevel=True
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False) as w:
            self.check_round_trip(df, nthreads=2)
        # we have an extra FutureWarning because of #GH23752
        assert any(expected_warning in str(x) for x in w)

        # TODO: make the warning work with check_stacklevel=True
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False) as w:
            self.check_round_trip(df, nthreads=1)
        # we have an extra FutureWarnings because of #GH23752
        assert any(expected_warning in str(x) for x in w)

    def test_rw_use_threads(self):
        df = pd.DataFrame({"A": np.arange(100000)})
        self.check_round_trip(df, use_threads=True)
        self.check_round_trip(df, use_threads=False)

    def test_write_with_index(self):

        df = pd.DataFrame({"A": [1, 2, 3]})
        self.check_round_trip(df)

        # non-default index
        for index in [
            [2, 3, 4],
            pd.date_range("20130101", periods=3),
            list("abc"),
            [1, 3, 4],
            pd.MultiIndex.from_tuples([("a", 1), ("a", 2), ("b", 1)]),
        ]:

            df.index = index
            self.check_error_on_write(df, ValueError)

        # index with meta-data
        df.index = [0, 1, 2]
        df.index.name = "foo"
        self.check_error_on_write(df, ValueError)

        # column multi-index
        df.index = [0, 1, 2]
        df.columns = (pd.MultiIndex.from_tuples([("a", 1), ("a", 2), ("b", 1)]),)
        self.check_error_on_write(df, ValueError)

    def test_path_pathlib(self):
        df = tm.makeDataFrame().reset_index()
        result = tm.round_trip_pathlib(df.to_feather, pd.read_feather)
        tm.assert_frame_equal(df, result)

    def test_path_localpath(self):
        df = tm.makeDataFrame().reset_index()
        result = tm.round_trip_localpath(df.to_feather, pd.read_feather)
        tm.assert_frame_equal(df, result)