code: def test_ls_none(data, runner):
      inputfile = str(data.join("RGB.byte.tif"))
      result = runner.invoke(cli, ["overview", inputfile, "--ls"])
      assert result.exit_code == 0
      expected = "Overview factors:\n  Band 1: None (method: 'unknown')\n  Band 2: None (method: 'unknown')\n  Band 3: None (method: 'unknown')\n"
      assert result.output == expected
  
file_path: rasterio/tests/test_rio_overview.py
imports: import logging
  import sys
  import pytest
  from rasterio.rio.main import main_group
  from rasterio.rio.overview import get_maximum_overview_level
label_desc: Use image node_id 2 for calling a global function with example usage: test_ls_none(data, runner) without return types