code: def test_uses_correct_dataset_reader(self):
      # We're going to use a fake predictor for this test, just checking that we loaded the
      # correct dataset reader.  We'll also create a fake dataset reader that subclasses the
      # expected one, and specify that one for validation.
      @Predictor.register("test-predictor")
      class _TestPredictor(Predictor):
          def dump_line(self, outputs: JsonDict) -> str:
              data = {"dataset_reader_type": type(self._dataset_reader).__name__}  # type: ignore
              return json.dumps(data) + "\n"
  
          def load_line(self, line: str) -> JsonDict:
              raise NotImplementedError
  
      @DatasetReader.register("fake-reader")
      class FakeDatasetReader(TextClassificationJsonReader):
          pass
  
      # --use-dataset-reader argument only should use validation
      sys.argv = [
          "__main__.py",  # executable
          "predict",  # command
          str(self.classifier_model_path),
          str(self.classifier_data_path),  # input_file
          "--output-file",
          str(self.outfile),
          "--overrides",
          '{"validation_dataset_reader": {"type": "fake-reader"}}',
          "--silent",
          "--predictor",
          "test-predictor",
          "--use-dataset-reader",
      ]
      main()
      assert os.path.exists(self.outfile)
      with open(self.outfile, "r") as f:
          results = [json.loads(line) for line in f]
          assert (
              results[0]["dataset_reader_type"] == "FakeDatasetReader"
          )
  
      # --use-dataset-reader, override with train
      sys.argv = [
          "__main__.py",  # executable
          "predict",  # command
          str(self.classifier_model_path),
          str(self.classifier_data_path),  # input_file
          "--output-file",
          str(self.outfile),
          "--overrides",
          '{"validation_dataset_reader": {"type": "fake-reader"}}',
          "--silent",
          "--predictor",
          "test-predictor",
          "--use-dataset-reader",
          "--dataset-reader-choice",
          "train",
      ]
      main()
      assert os.path.exists(self.outfile)
      with open(self.outfile, "r") as f:
          results = [json.loads(line) for line in f]
          assert (
              results[0]["dataset_reader_type"]
              == "TextClassificationJsonReader"
          )
  
      # --use-dataset-reader, override with validation
      sys.argv = [
          "__main__.py",  # executable
          "predict",  # command
          str(self.classifier_model_path),
          str(self.classifier_data_path),  # input_file
          "--output-file",
          str(self.outfile),
          "--overrides",
          '{"validation_dataset_reader": {"type": "fake-reader"}}',
          "--silent",
          "--predictor",
          "test-predictor",
          "--use-dataset-reader",
          "--dataset-reader-choice",
          "validation",
      ]
      main()
      assert os.path.exists(self.outfile)
      with open(self.outfile, "r") as f:
          results = [json.loads(line) for line in f]
          assert (
              results[0]["dataset_reader_type"] == "FakeDatasetReader"
          )
  
      # No --use-dataset-reader flag, fails because the loading logic
      # is not implemented in the testing predictor
      sys.argv = [
          "__main__.py",  # executable
          "predict",  # command
          str(self.classifier_model_path),
          str(self.classifier_data_path),  # input_file
          "--output-file",
          str(self.outfile),
          "--overrides",
          '{"validation_dataset_reader": {"type": "fake-reader"}}',
          "--silent",
          "--predictor",
          "test-predictor",
      ]
      with pytest.raises(NotImplementedError):
          main()
  
imports: import argparse
  import csv
  import io
  import json
  import os
  import pathlib
  import shutil
  import sys
  import tempfile
  import pytest
  from allennlp.commands import main
  from allennlp.commands.predict import Predict
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.common.util import JsonDict, push_python_path
  from allennlp.data.dataset_readers import DatasetReader, TextClassificationJsonReader
  from allennlp.models import Model
  from allennlp.models.archival import load_archive
  from allennlp.predictors import Predictor, TextClassifierPredictor
label_desc: Use image node_id 5 for calling the TestPredict obj's underlying member method code with example usage: obj.test_uses_correct_dataset_reader() and returns: unknown