code: def testLoadCsvColumnNames(self):
      source_data_dir = os.path.join(
          os.path.dirname(__file__), "testdata"
      )
      test_file = os.path.join(source_data_dir, "test.csv")
      column_names = io_utils.load_csv_column_names(test_file)
      self.assertListEqual(["a", "b", "c", "d"], column_names)
  
imports: import os
  from unittest import mock
  import tensorflow
  from tfx.dsl.io import fileio
  from tfx.utils import io_utils
  from tensorflow.python.lib.io import file_io
label_desc: Use image node_id 18 for calling the IoUtilsTest obj's underlying member method code with example usage: obj.testLoadCsvColumnNames() without return types