code: def test_clean_names_case_type_preserve(spark_df):
      """Tests case_type parameter 'preserve' takes effect."""
      spark_df = spark_df.clean_names(case_type="preserve")
      expected_columns = [
          "a",
          "Bell_Chart",
          "decorated_elephant",
          "animals@#$%^",
          "cities",
      ]
      assert set(spark_df.columns) == set(expected_columns)
  
file_path: pyjanitor/tests/spark/functions/test_clean_names_spark.py
imports: import pytest
  from helpers import running_on_ci
  from janitor.errors import JanitorError
  import janitor.spark
label_desc: Use image node_id 4 for calling a global function with example usage: test_clean_names_case_type_preserve(spark_df) without return types