class_docstr: Test the IciL1bNCFileHandler reader.
class_docstr_tok: ["Test","the","IciL1bNCFileHandler","reader","."]
docstr: Test calibrate calls calibrate_bt.
docstr_tok: ["Test","calibrate","calls","calibrate_bt","."]
code: def test_calibrate_calls_calibrate_bt(
      self,
      mocked_calibrate_bt,
      reader,
  ):
      """Test calibrate calls calibrate_bt."""
      variable = xr.DataArray(
          np.array(
              [
                  [0.060, 0.065, 0.070, 0.075],
                  [0.080, 0.085, 0.090, 0.095],
              ]
          ),
          dims=("n_scan", "n_samples"),
      )
      dataset_info = {
          "calibration": "brightness_temperature",
          "chan_index": 2,
      }
      reader._calibrate(variable, dataset_info)
      mocked_calibrate_bt.assert_called_once_with(
          variable,
          6.0,
          1.0,
          0.0,
      )
  
imports: from datetime import datetime
  from unittest.mock import patch
  import numpy
  import pytest
  import xarray
  from netCDF4 import Dataset
  from satpy.readers.ici_l1b_nc import IciL1bNCFileHandler, InterpolationType
label_desc: Use image node_id 12 for calling the TestIciL1bNCFileHandler obj's underlying member method code with example usage: obj.test_calibrate_calls_calibrate_bt(mocked_calibrate_bt, reader) without return types