code: def test_read_files(self):
      train_info = SplitInfo(name="train", num_examples=100)
      test_info = SplitInfo(name="test", num_examples=100)
      split_dict = SplitDict()
      split_dict.add(train_info)
      split_dict.add(test_info)
      info = DatasetInfo(splits=split_dict)
  
      with tempfile.TemporaryDirectory() as tmp_dir:
          reader = ReaderTest(tmp_dir, info)
  
          files = [
              {"filename": os.path.join(tmp_dir, "train")},
              {
                  "filename": os.path.join(tmp_dir, "test"),
                  "skip": 10,
                  "take": 10,
              },
          ]
          dset = Dataset(
              **reader.read_files(
                  files, original_instructions="train+test[10:20]"
              )
          )
          self.assertEqual(dset.num_rows, 110)
          self.assertEqual(dset.num_columns, 1)
          del dset
  
imports: import os
  import tempfile
  from pathlib import Path
  from unittest import TestCase
  import pyarrow
  import pytest
  from datasets.arrow_dataset import Dataset
  from datasets.arrow_reader import ArrowReader, BaseReader, FileInstructions, ReadInstruction, make_file_instructions
  from datasets.info import DatasetInfo
  from datasets.splits import NamedSplit, Split, SplitDict, SplitInfo
  from .utils import assert_arrow_memory_doesnt_increase, assert_arrow_memory_increases
label_desc: Use image node_id 3 for calling the BaseReaderTest obj's underlying member method code with example usage: obj.test_read_files() without return types