class_docstr: Test the filehandler.
class_docstr_tok: ["Test","the","filehandler","."]
docstr: Test reading the lon and lats.
docstr_tok: ["Test","reading","the","lon","and","lats","."]
code: def test_navigation(self):
      """Test reading the lon and lats."""
      with tempfile.TemporaryFile() as tmpfile:
          self._header.tofile(tmpfile)
          tmpfile.seek(22016, 0)
          self._data.tofile(tmpfile)
  
          fh = AVHRRAAPPL1BFile(
              tmpfile, self.filename_info, self.filetype_info
          )
          info = {}
          key = make_dataid(name="longitude")
          res = fh.get_dataset(key, info)
          assert np.all(res == 0)
          key = make_dataid(name="latitude")
          res = fh.get_dataset(key, info)
          assert np.all(res == 0)
  
imports: import datetime
  import os
  import tempfile
  import unittest
  from contextlib import suppress
  from unittest import mock
  import numpy
  from satpy.readers.aapp_l1b import _HEADERTYPE, _SCANTYPE, AVHRRAAPPL1BFile
  from satpy.tests.utils import make_dataid
label_desc: Use image node_id 4 for calling the TestAAPPL1BAllChannelsPresent obj's underlying member method code with example usage: obj.test_navigation() without return types