code: def test_set_tbl_cols() -> None:
      df = pl.DataFrame(
          {"a": [1, 2, 3], "b": [4, 5, 6], "c": [7, 8, 9]}
      )
  
      pl.Config.set_tbl_cols(1)
      assert str(df).split("\n")[2] == "│ a   ┆ … │"
      pl.Config.set_tbl_cols(2)
      assert str(df).split("\n")[2] == "│ a   ┆ … ┆ c   │"
      pl.Config.set_tbl_cols(3)
      assert str(df).split("\n")[2] == "│ a   ┆ b   ┆ c   │"
  
      df = pl.DataFrame(
          {
              "a": [1, 2, 3],
              "b": [4, 5, 6],
              "c": [7, 8, 9],
              "d": [10, 11, 12],
          }
      )
      pl.Config.set_tbl_cols(2)
      assert str(df).split("\n")[2] == "│ a   ┆ … ┆ d   │"
      pl.Config.set_tbl_cols(3)
      assert str(df).split("\n")[2] == "│ a   ┆ b   ┆ … ┆ d   │"
      pl.Config.set_tbl_cols(-1)
      assert str(df).split("\n")[2] == "│ a   ┆ b   ┆ c   ┆ d   │"
  
imports: from __future__ import annotations
  import os
  from pathlib import Path
  from typing import Any, Iterator
  import pytest
  import polars
  import polars.polars
  from polars.config import _POLARS_CFG_ENV_VARS
label_desc: Use image node_id 5 for calling a global function with example usage: test_set_tbl_cols() without return types