class_docstr: Tests for the AHI HSD file handler.
class_docstr_tok: ["Tests","for","the","AHI","HSD","file","handler","."]
docstr: Test header reading.
docstr_tok: ["Test","header","reading","."]
code: def test_read_header(self, *mocks):
      """Test header reading."""
      with _fake_hsd_handler() as fh:
          fh._read_header(mock.MagicMock())
  
imports: from __future__ import annotations
  import contextlib
  import unittest
  import warnings
  from datetime import datetime
  from typing import Any, Dict
  from unittest import mock
  import dask.array
  import numpy
  import pytest
  from satpy.readers.ahi_hsd import AHIHSDFileHandler
  from satpy.readers.utils import get_geostationary_mask
  from satpy.tests.utils import make_dataid
label_desc: Use image node_id 3 for calling the TestAHIHSDFileHandler obj's underlying member method code with example usage: obj.test_read_header() without return types