code: def test_write_and_read_plain_json(self):
      json_path = os.path.join(resource_path, "json/plain-json")
      # write as a json
      self.sc.write(self.df, CryptoMode.PLAIN_TEXT).mode(
          "overwrite"
      ).json(json_path)
  
      # read from a json
      df_from_json = self.sc.read(CryptoMode.PLAIN_TEXT).json(json_path)
  
      content = "\n".join(
          [
              str(v["language"]) + "," + str(v["user"])
              for v in df_from_json.orderBy("language").collect()
          ]
      )
      self.assertEqual(content, self.data_content)
  
file_path: BigDL/python/ppml/test/bigdl/ppml/test_ppml_context.py
imports: import unittest
  import os
  import random
  import shutil
  from bigdl.ppml.ppml_context import *
  from pyspark.sql.types import StructType, StructField, StringType
label_desc: Use image node_id 11 for calling the TestPPMLContext obj's underlying member method code with example usage: obj.test_write_and_read_plain_json() without return types