import numpy as np
import pytest

from pandas import SparseDataFrame, read_csv
from pandas.util import testing as tm


@pytest.mark.filterwarnings("ignore:Sparse:FutureWarning")
@pytest.mark.filterwarnings("ignore:DataFrame.to_sparse:FutureWarning")
class TestSparseDataFrameToCsv:
    fill_values = [np.nan, 0, None, 1]

    @pytest.mark.parametrize("fill_value", fill_values)
    def test_to_csv_sparse_dataframe(self, fill_value):
        # GH19384
        sdf = SparseDataFrame(
            {"a": type(self).fill_values}, default_fill_value=fill_value
        )

        with tm.ensure_clean("sparse_df.csv") as path:
            sdf.to_csv(path, index=False)
            df = read_csv(path, skip_blank_lines=False)

            tm.assert_sp_frame_equal(df.to_sparse(fill_value=fill_value), sdf)