class_docstr: Test the filehandler.
class_docstr_tok: ["Test","the","filehandler","."]
docstr: Test the reading.
docstr_tok: ["Test","the","reading","."]
code: def test_read(self):
      """Test the reading."""
      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 = {}
          mins = []
          maxs = []
          for name in ["1", "2", "3a"]:
              key = make_dataid(name=name, calibration="reflectance")
              res = fh.get_dataset(key, info)
              assert res.min() == 0
              assert res.max() >= 100
              mins.append(res.min().values)
              maxs.append(res.max().values)
              if name == "3a":
                  assert np.all(np.isnan(res[:2, :]))
  
          for name in ["3b", "4", "5"]:
              key = make_dataid(name=name, calibration="reflectance")
              res = fh.get_dataset(key, info)
              mins.append(res.min().values)
              maxs.append(res.max().values)
              if name == "3b":
                  assert np.all(np.isnan(res[2:, :]))
  
          np.testing.assert_allclose(
              mins,
              [0.0, 0.0, 0.0, 204.10106939, 103.23477235, 106.42609758],
          )
          np.testing.assert_allclose(
              maxs,
              [
                  108.40391775,
                  107.68545158,
                  106.80061233,
                  337.71416096,
                  355.15898219,
                  350.87182166,
              ],
          )
  
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 2 for calling the TestAAPPL1BAllChannelsPresent obj's underlying member method code with example usage: obj.test_read() without return types