class_docstr: Set up executor: mock data handler
code: def save_file(self, name, df):
      file_path = tempfile.mktemp(prefix="mindsdb_file_")
      df.to_parquet(file_path)
      self.file_controller.save_file(name, file_path, name)
  
imports: import copy
  import datetime
  import json
  import os
  import sys
  import tempfile
  from unittest import mock
  from pathlib import Path
  import duckdb
  import numpy
  import pandas
  from mindsdb_sql.render.sqlalchemy_render import SqlalchemyRender
  from mindsdb_sql import parse_sql
label_desc: Use image node_id 3 for calling the BaseExecutorTest obj's underlying member method code with example usage: obj.save_file(name, df) without return types