class_docstr: Test the HRIT prologue file handler.
class_docstr_tok: ["Test","the","HRIT","prologue","file","handler","."]
docstr: Set up the test case.
docstr_tok: ["Set","up","the","test","case","."]
code: def setUp(self, *mocks):
      """Set up the test case."""
      fh = setup.get_fake_file_handler(
          observation_start_time=datetime(2016, 3, 3, 0, 0),
          nlines=464,
          ncols=3712,
      )
      self.reader = fh.prologue_
  
imports: import unittest
  from datetime import datetime
  from unittest import mock
  import numpy
  import pytest
  import xarray
  from numpy import testing
  from pyproj import CRS
  import satpy.tests.reader_tests.test_seviri_l1b_hrit_setup
  from satpy.readers.seviri_l1b_hrit import HRITMSGEpilogueFileHandler, HRITMSGFileHandler, HRITMSGPrologueFileHandler
  from satpy.tests.reader_tests.test_seviri_base import ORBIT_POLYNOMIALS_INVALID
  from satpy.tests.reader_tests.test_seviri_l1b_calibration import TestFileHandlerCalibrationBase
  from satpy.tests.utils import assert_attrs_equal, make_dataid
label_desc: Use image node_id 1 for calling the TestHRITMSGPrologueFileHandler obj's underlying member method code with example usage: obj.setUp() without return types