code: def test_trainer_serializes(self):
      serialization_dir = self.TEST_DIR / "serialization_dir"
      trainer = NoOpTrainer(
          serialization_dir=serialization_dir, model=self.model
      )
      metrics = trainer.train()
      assert metrics == {}
      assert os.path.exists(serialization_dir / "best.th")
      assert os.path.exists(serialization_dir / "vocabulary")
  
file_path: allennlp/tests/training/no_op_trainer_test.py
imports: import os
  from typing import Dict
  import torch
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.data import Vocabulary
  from allennlp.data.dataset_readers import SequenceTaggingDatasetReader
  from allennlp.models.model import Model
  from allennlp.training import NoOpTrainer
label_desc: Use image node_id 2 for calling the TestNoOpTrainer obj's underlying member method code with example usage: obj.test_trainer_serializes() without return types