class_docstr: Test the area helpers.
docstr: Test the FSFile bz2 file unzipping techniques.
code: def test_unzip_FSFile(self, bz2_mock):
      """Test the FSFile bz2 file unzipping techniques."""
      mock_bz2_decompress = mock.MagicMock()
      mock_bz2_decompress.return_value = b"TEST_DECOMPRESSED"
  
      segment = 3
      segmentstr = str(segment).zfill(2)
  
      # test zipped FSFile unzipped in fly (decompress shouldn't be called)
      mem_fs = MemoryFileSystem()
      mem_file = MemoryFile(
          fs=mem_fs,
          path="{}test.DAT.bz2".format(mem_fs.root_marker),
          data=b"TEST",
      )
      mem_file.commit()
      fsf = FSFile(mem_file)
  
      new_fname = hf.unzip_file(fsf, prefix=segmentstr)
      mock_bz2_decompress.assert_not_called
      bz2_mock.assert_not_called
      assert os.path.exists(new_fname)
      assert os.path.split(new_fname)[1][0:2] == segmentstr
      if os.path.exists(new_fname):
          os.remove(new_fname)
  
      # test FSFile without unzipping in fly (decompress should be called)
      mem_file = MemoryFile(
          fs=mem_fs,
          path="{}test.DAT.bz2".format(mem_fs.root_marker),
          data=bytes.fromhex("425A68") + b"TEST",
      )
      mem_file.commit()
      fsf = FSFile(mem_file)
  
      new_fname = hf.unzip_file(fsf, prefix=segmentstr)
      mock_bz2_decompress.assert_called
      bz2_mock.assert_called
      assert os.path.exists(new_fname)
      assert os.path.split(new_fname)[1][0:2] == segmentstr
      if os.path.exists(new_fname):
          os.remove(new_fname)
  
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 13 for calling the TestHelpers obj's underlying member method code with example usage: obj.test_unzip_FSFile(bz2_mock) without return types