code: def test_retrieve(self):
      config = self.get_config()
      retriever = self.get_dummy_retriever()
      tokenizer = retriever.tokenizer
  
      retrieved_block_ids = np.array([0, 3], dtype=np.long)
      question_input_ids = tokenizer(["Test question"]).input_ids
      answer_ids = tokenizer(
          ["the fourth"],
          add_special_tokens=False,
          return_token_type_ids=False,
          return_attention_mask=False,
      ).input_ids
      max_length = config.reader_seq_len
  
      has_answers, start_pos, end_pos, concat_inputs = retriever(
          retrieved_block_ids,
          question_input_ids,
          answer_ids=answer_ids,
          max_length=max_length,
          return_tensors="np",
      )
  
      self.assertEqual(len(has_answers), 2)
      self.assertEqual(len(start_pos), 2)
      self.assertEqual(len(end_pos), 2)
      self.assertEqual(concat_inputs.input_ids.shape, (2, 10))
      self.assertEqual(concat_inputs.attention_mask.shape, (2, 10))
      self.assertEqual(concat_inputs.token_type_ids.shape, (2, 10))
      self.assertEqual(concat_inputs.special_tokens_mask.shape, (2, 10))
      self.assertEqual(
          tokenizer.convert_ids_to_tokens(concat_inputs.input_ids[0]),
          [
              "[CLS]",
              "test",
              "question",
              "[SEP]",
              "this",
              "is",
              "the",
              "first",
              "record",
              "[SEP]",
          ],
      )
      self.assertEqual(
          tokenizer.convert_ids_to_tokens(concat_inputs.input_ids[1]),
          [
              "[CLS]",
              "test",
              "question",
              "[SEP]",
              "this",
              "is",
              "the",
              "fourth",
              "record",
              "[SEP]",
          ],
      )
  
imports: import os
  import shutil
  import tempfile
  from unittest import TestCase
  from unittest.mock import patch
  import numpy
  from datasets import Dataset
  from transformers.models.realm.configuration_realm import RealmConfig
  from transformers.models.realm.retrieval_realm import _REALM_BLOCK_RECORDS_FILENAME, RealmRetriever
  from transformers.models.realm.tokenization_realm import VOCAB_FILES_NAMES, RealmTokenizer
label_desc: Use image node_id 8 for calling the RealmRetrieverTest obj's underlying member method code with example usage: obj.test_retrieve() without return types