class_docstr: Test case for the downloading and preparing LUTs.
docstr: Test that the FTP library is called for downloading LUTS.
docstr_tok: ["Test","that","the","FTP","library","is","called","for","downloading","LUTS","."]
code: def test_download_luts(self, mock_dl, mock_shutil):
      """Test that the FTP library is called for downloading LUTS."""
      m = mock.mock_open()
      with mock.patch(
          "satpy.readers.ahi_l1b_gridded_bin.open", m, create=True
      ):
          self.fh._download_luts("/test_file")
          mock_dl.assert_called()
          mock_shutil.assert_called()
  
imports: import os
  import shutil
  import tempfile
  import unittest
  from unittest import mock
  import dask.array
  import numpy
  import pytest
  from pyresample.geometry import AreaDefinition
  from satpy.readers.ahi_l1b_gridded_bin import AHI_LUT_NAMES, AHIGriddedFileHandler
label_desc: Use image node_id 5 for calling the TestAHIGriddedLUTs obj's underlying member method code with example usage: obj.test_download_luts(mock_dl, mock_shutil) without return types