class_docstr: Test the Scene object's `.load` method for datasets coming from a reader.
class_docstr_tok: ["Test","the","Scene","object","'s","`",".load","`","method","for","datasets","coming","from","a","reader","."]
docstr: Test loading a dataset that has two calibration variations.
code: def test_load_ds4_cal(self):
      """Test loading a dataset that has two calibration variations."""
      scene = Scene(filenames=["fake1_1.txt"], reader="fake1")
      scene.load(["ds4"])
      loaded_ids = list(scene._datasets.keys())
      assert len(loaded_ids) == 1
      assert loaded_ids[0]["calibration"] == "reflectance"
  
imports: from unittest import mock
  import pytest
  import xarray
  from dask import array
  from satpy import Scene
  from satpy.tests.utils import make_cid, make_dataid, make_dsq, spy_decorator
label_desc: Use image node_id 5 for calling the TestLoadingReaderDatasets obj's underlying member method code with example usage: obj.test_load_ds4_cal() without return types