code: def test_mock_movielens_schema__has_default_col_names(size):
      df = MockMovielensSchema.example(size=size)
      for col_name in DEFAULT_HEADER:
          assert col_name in df.columns
  
imports: import os
  import gc
  import pandas
  from pandas.core.series import Series
  import pytest
  from pytest_mock import MockerFixture
  from recommenders.utils.constants import DEFAULT_GENRE_COL, DEFAULT_TITLE_COL
  from recommenders.datasets.movielens import MockMovielensSchema
  from recommenders.datasets.movielens import load_pandas_df, load_spark_df, load_item_df, download_movielens, extract_movielens
  from recommenders.datasets.movielens import DATA_FORMAT, MOCK_DATA_FORMAT, DEFAULT_HEADER, DEFAULT_ITEM_COL, DEFAULT_USER_COL
label_desc: Use image node_id 1 for calling a global function with example usage: test_mock_movielens_schema__has_default_col_names(size) without return types