class_docstr: Test the MWSL1BFile reader.
docstr: Test get auxillary dataset which is not present but supposed to be in file.
docstr_tok: ["Test","get","auxillary","dataset","which","is","not","present","but","supposed","to","be","in","file","."]
code: def test_get_dataset_aux_data_expected_data_missing(
      self, caplog, reader
  ):
      """Test get auxillary dataset which is not present but supposed to be in file."""
      dataset_id = {"name": "surface_type"}
      dataset_info = {"file_key": "non/existing"}
  
      with caplog.at_level(logging.ERROR):
          with pytest.raises(KeyError) as exec_info:
              _ = reader.get_dataset(dataset_id, dataset_info)
  
      assert (
          str(exec_info.value) == "'data/navigation/mws_surface_type'"
      )
  
      log_output = (
          "Could not find key data/navigation/mws_surface_type in NetCDF file,"
          + " no valid Dataset created"
      )
      assert log_output in caplog.text
  
imports: import logging
  from datetime import datetime
  from unittest.mock import patch
  import numpy
  import pytest
  import xarray
  from netCDF4 import Dataset
  from satpy.readers.mws_l1b import MWSL1BFile, get_channel_index_from_name
label_desc: Use image node_id 15 for calling the TestMwsL1bNCFileHandler obj's underlying member method code with example usage: obj.test_get_dataset_aux_data_expected_data_missing(caplog, reader) without return types