code: def test_read_ray_dataset(ray_start_regular):
      test_df1 = pd.DataFrame(
          {
              "a": np.arange(10).astype(np.int64, copy=False),
              "b": [f"s{i}" for i in range(10)],
          }
      )
      test_df2 = pd.DataFrame(
          {
              "a": np.arange(10).astype(np.int64, copy=False),
              "b": [f"s{i}" for i in range(10)],
          }
      )
      df = pd.concat([test_df1, test_df2])
      ds = ray.data.from_pandas_refs(
          [ray.put(test_df1), ray.put(test_df2)]
      )
      mdf = read_ray_dataset(ds)
  
      assert mdf.shape[1] == 2
      pd.testing.assert_index_equal(
          df.columns, mdf.columns_value.to_pandas()
      )
      pd.testing.assert_series_equal(df.dtypes, mdf.dtypes)
  
      mdf = tile(mdf)
      assert len(mdf.chunks) == 2
      for chunk in mdf.chunks:
          assert isinstance(chunk.op, DataFrameReadRayDataset)
  
imports: import os
  import tempfile
  import shutil
  import string
  from collections import OrderedDict
  import numpy
  import pandas
  import pytest
  from ....None import tensor
  from ....config import option_context
  from ....core import tile
  from ....tests.core import require_ray
  from ....utils import lazy_import
  from ...core import IndexValue, DatetimeIndex, Int64Index, Float64Index, MultiIndex
  from ..core import merge_small_files
  from ..dataframe import from_pandas
  from ..date_range import date_range
  from ..from_records import from_records
  from ..from_tensor import dataframe_from_tensor, series_from_tensor, dataframe_from_1d_tileables
  from ..index import from_pandas, from_tileable
  from ..read_csv import read_csv, DataFrameReadCSV
  from ..read_sql import read_sql_table, read_sql_query, DataFrameReadSQL
  from ..read_raydataset import read_ray_dataset, DataFrameReadRayDataset, read_ray_mldataset, DataFrameReadMLDataset
  from ...utils import ray_deprecate_ml_dataset
  from ..series import from_pandas
label_desc: Use image node_id 10 for calling a global function with example usage: test_read_ray_dataset(ray_start_regular) without return types