class_docstr: Test GRIB Reader.
class_docstr_tok: ["Test","GRIB","Reader","."]
code: def _get_test_datasets(self, dataids, fake_pygrib=None):
      from satpy.readers import load_reader
  
      if fake_pygrib is None:
          fake_pygrib = FakeGRIB()
  
      with mock.patch("satpy.readers.grib.pygrib") as pg:
          pg.open.return_value = fake_pygrib
          r = load_reader(self.reader_configs)
          loadables = r.select_files_from_pathnames(
              [
                  "gfs.t18z.sfluxgrbf106.grib2",
              ]
          )
          r.create_filehandlers(loadables)
          datasets = r.load(dataids)
      return datasets
  
imports: import os
  import sys
  from unittest import mock
  import numpy
  import pytest
  import xarray
  from satpy.dataset import DataQuery
label_desc: Use image node_id 3 for calling the TestGRIBReader obj's underlying member method code with example usage: obj._get_test_datasets(dataids, fake_pygrib) and returns: datasets