code: def test_write_file_uri(self):
      ioctx = IOContext(self.test_dir, None, 0, None)
      writer = JsonWriter(
          "file://" + self.test_dir,
          ioctx,
          max_file_size=1000,
          compress_columns=["obs"],
      )
      self.assertEqual(len(os.listdir(self.test_dir)), 0)
      writer.write(SAMPLES)
      writer.write(SAMPLES)
      self.assertEqual(len(os.listdir(self.test_dir)), 1)
  
imports: import glob
  import json
  import numpy
  import os
  import random
  import shutil
  import tempfile
  import unittest
  import ray
  from ray.tune.registry import register_env, register_input, registry_get_input, registry_contains_input
  from ray.rllib.algorithms.algorithm_config import AlgorithmConfig
  from ray.rllib.algorithms.pg import PGConfig
  from ray.rllib.algorithms.ppo import PPOConfig
  from ray.rllib.examples.env.multi_agent import MultiAgentCartPole
  from ray.rllib.offline import IOContext, JsonWriter, JsonReader, InputReader, ShuffledInput, DatasetWriter
  from ray.rllib.offline.json_reader import from_json_data
  from ray.rllib.offline.json_writer import _to_json_dict, _to_json
  from ray.rllib.policy.sample_batch import SampleBatch, convert_ma_batch_to_sample_batch
  from ray.rllib.utils.test_utils import framework_iterator
label_desc: Use image node_id 5 for calling the JsonIOTest obj's underlying member method code with example usage: obj.test_write_file_uri() without return types