code: def test_get_scale_factors_for_units_unsupported_units():
      """Test get scale factors for units, when units are not supported."""
      factors = xr.DataArray(
          da.from_array(DEFAULT_FILE_FACTORS, chunks=1)
      )
      file_units = "unknown unit"
      output_units = "%"
      with pytest.raises(
          ValueError,
          match="Don't know how to convert 'unknown unit' to '%'",
      ):
          _ = _get_scale_factors_for_units(
              factors, file_units, output_units
          )
  
file_path: satpy/satpy/tests/reader_tests/test_viirs_atms_utils.py
imports: import logging
  import dask.array
  import numpy
  import pytest
  import xarray
  from satpy.readers.viirs_atms_sdr_base import _get_file_units, _get_scale_factors_for_units
  from satpy.tests.utils import make_dataid
label_desc: Use image node_id 2 for calling a global function with example usage: test_get_scale_factors_for_units_unsupported_units() without return types