class_docstr: Test the area helpers.
docstr: Test the generic_open method with filename (str).
code: def test_generic_open_filename(self, open_mock):
      """Test the generic_open method with filename (str)."""
      mock_fn_open = mock.MagicMock()
      mock_fn_open.read.return_value = b"TEST"
      open_mock.return_value = mock_fn_open
  
      filename = "test.DAT"
      with hf.generic_open(filename) as file_object:
          data = file_object.read()
          assert data == b"TEST"
  
      assert mock_fn_open.read.called
  
imports: import os
  import unittest
  from datetime import datetime
  from unittest import mock
  import dask.array
  import numpy
  import numpy.testing
  import pyresample.geometry
  import pytest
  import xarray
  from fsspec.implementations.memory import MemoryFile, MemoryFileSystem
  from pyproj import CRS
  from satpy.readers import FSFile
  from satpy.readers import utils
label_desc: Use image node_id 12 for calling the TestHelpers obj's underlying member method code with example usage: obj.test_generic_open_filename(open_mock) without return types