def test_to_from_buffer(df: pl.DataFrame) -> None:
buf = io.BytesIO()
df.write_csv(buf)
buf.seek(0)
read_df = pl.read_csv(buf, parse_dates=True)
read_df = read_df.with_columns(
[pl.col("cat").cast(pl.Categorical), pl.col("time").cast(pl.Time)]
)
assert df.frame_equal(read_df)
def test_to_from_file(io_test_dir: str, df: pl.DataFrame) -> None:
df = df.drop("strings_nulls")
f = os.path.join(io_test_dir, "small.csv")
df.write_csv(f)
read_df = pl.read_csv(f, parse_dates=True)
read_df = read_df.with_columns(
[pl.col("cat").cast(pl.Categorical), pl.col("time").cast(pl.Time)]
)
assert df.frame_equal(read_df)