code: def test_sql_string_case() -> None:
      df = pl.DataFrame({"words": ["Test SOME words"]})
  
      with pl.SQLContext(frame=df) as ctx:
          res = ctx.execute(
              """
              SELECT
                words,
                INITCAP(words) as cap,
                UPPER(words) as upper,
                LOWER(words) as lower,
              FROM frame
              """
          ).collect()
  
          assert res.to_dict(as_series=False) == {
              "words": ["Test SOME words"],
              "cap": ["Test Some Words"],
              "upper": ["TEST SOME WORDS"],
              "lower": ["test some words"],
          }
  
imports: from __future__ import annotations
  import datetime
  import math
  from pathlib import Path
  import pytest
  import polars
  import polars.selectors
  from polars.exceptions import ComputeError, InvalidOperationError
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 26 for calling a global function with example usage: test_sql_string_case() without return types