code: def test_merge_dfs_0(
      merge_to, stage, expected_dfs, expected_group, original_dfs
  ):
      # Test building `actual_merged_df` via `merge_dfs`
      actual_merged_df = merge_dfs(merge_to, stage, original_dfs)
      expected_merged_df = build_merged_df(
          expected_dfs, expected_group, original_dfs
      )
      assert actual_merged_df.equals(expected_merged_df)
      # Test splitting `actual_merged_df` via `split_merged_df`
      actual_split_dfs = split_merged_df(actual_merged_df)
      expected_split_dfs_names = [
          f"{_}_{expected_group}" for _ in expected_dfs
      ]
      expected_split_dfs = {
          _: original_dfs[_] for _ in expected_split_dfs_names
      }
      assert all(
          v.equals(expected_split_dfs[k])
          for k, v in actual_split_dfs.items()
      )
  
file_path: hyperparameter_hunter/tests/test_feature_engineering.py
imports: from hyperparameter_hunter.feature_engineering import merge_dfs, split_merged_df
  from hyperparameter_hunter.feature_engineering import DatasetNameReport, validate_dataset_names
  from hyperparameter_hunter.feature_engineering import get_engineering_step_params
  import pandas
  import pytest
label_desc: Use image node_id 2 for calling a global function with example usage: test_merge_dfs_0(merge_to, stage, expected_dfs, expected_group, original_dfs) without return types