class_docstr: Test the NativeMSGFileHandler.
class_docstr_tok: ["Test","the","NativeMSGFileHandler","."]
docstr: Test the derivation of the available channel list.
docstr_tok: ["Test","the","derivation","of","the","available","channel","list","."]
code: def test_get_available_channels(self):
      """Test the derivation of the available channel list."""
      available_chs = get_available_channels(TEST1_HEADER_CHNLIST)
      trues = (
          "WV_062",
          "WV_073",
          "IR_108",
          "VIS006",
          "VIS008",
          "IR_120",
      )
      for bandname in AVAILABLE_CHANNELS:
          if bandname in trues:
              assert available_chs[bandname]
          else:
              assert not available_chs[bandname]
  
      available_chs = get_available_channels(TEST2_HEADER_CHNLIST)
      trues = (
          "VIS006",
          "VIS008",
          "IR_039",
          "WV_062",
          "WV_073",
          "IR_087",
          "HRV",
      )
      for bandname in AVAILABLE_CHANNELS:
          if bandname in trues:
              assert available_chs[bandname]
          else:
              assert not available_chs[bandname]
  
      available_chs = get_available_channels(TEST3_HEADER_CHNLIST)
      for bandname in AVAILABLE_CHANNELS:
          assert available_chs[bandname]
  
imports: from __future__ import annotations
  import os
  import unittest
  import warnings
  from datetime import datetime
  from unittest import mock
  import dask.array
  import numpy
  import pytest
  import xarray
  from satpy.readers.eum_base import recarray2dict, time_cds_short
  from satpy.readers.seviri_l1b_native import ASCII_STARTSWITH, ImageBoundaries, NativeMSGFileHandler, Padder, get_available_channels, has_archive_header
  from satpy.tests.reader_tests.test_seviri_base import ORBIT_POLYNOMIALS, ORBIT_POLYNOMIALS_INVALID
  from satpy.tests.reader_tests.test_seviri_l1b_calibration import TestFileHandlerCalibrationBase
  from satpy.tests.utils import assert_attrs_equal, make_dataid
label_desc: Use image node_id 1 for calling the TestNativeMSGFileHandler obj's underlying member method code with example usage: obj.test_get_available_channels() without return types