class_docstr: Test the SAFE GRD file handler.
class_docstr_tok: ["Test","the","SAFE","GRD","file","handler","."]
docstr: Test the calibration routines.
docstr_tok: ["Test","the","calibration","routines","."]
code: def test_read_calibrated_natural(self, mocked_xarray_open):
      """Test the calibration routines."""
      calibration = mock.MagicMock()
      calibration.name = "sigma_nought"
      mocked_xarray_open.return_value.__getitem__.return_value = (
          xr.DataArray(
              da.from_array(np.array([[0, 1], [2, 3]])), dims=["y", "x"]
          )
      )
      xarr = self.test_fh.get_dataset(
          DataQuery(
              name="measurement",
              polarization="vv",
              calibration=calibration,
              quantity="natural",
          ),
          info=dict(),
      )
      np.testing.assert_allclose(xarr, [[np.nan, 2], [5, 10]])
  
imports: import unittest
  import unittest.mock
  from enum import Enum
  from io import BytesIO
  import dask.array
  import numpy
  import xarray
  from satpy.dataset import DataQuery
  from satpy.readers.sar_c_safe import SAFEXMLAnnotation, SAFEXMLCalibration, SAFEXMLNoise
label_desc: Use image node_id 3 for calling the TestSAFEGRD obj's underlying member method code with example usage: obj.test_read_calibrated_natural(mocked_xarray_open) without return types