code: def test_unionize_dataframe_categories_single(
      uniontest_df1, uniontest_df2, uniontest_df3
  ):
      udf1, udf2, udf3 = janitor.unionize_dataframe_categories(
          uniontest_df1,
          uniontest_df2,
          uniontest_df3,
          column_names="fruits",
      )
  
      # check that fruits did get unionized
  
      assert set(udf1["fruits"].dtype.categories) == set(
          udf2["fruits"].dtype.categories
      )
  
      assert set(udf1["fruits"].dtype.categories) == set(
          udf3["fruits"].dtype.categories
      )
  
      # check that jerbs did not when we didn't want it to
  
      assert not (
          set(udf1["jerbs"].dtype.categories)
          == set(udf2["jerbs"].dtype.categories)
      )
  
file_path: pyjanitor/tests/functions/test_unionize_dataframe_categories.py
imports: import pandas
  import pytest
  from pandas.testing import assert_frame_equal
  import janitor
label_desc: Use image node_id 7 for calling a global function with example usage: test_unionize_dataframe_categories_single(uniontest_df1, uniontest_df2, uniontest_df3) without return types