class_docstr: Test VIRR L1B Reader.
class_docstr_tok: ["Test","VIRR","L1B","Reader","."]
docstr: Test that FY3B files are recognized.
docstr_tok: ["Test","that","FY3B","files","are","recognized","."]
code: def test_fy3b_file(self):
      """Test that FY3B files are recognized."""
      from satpy.readers import load_reader
  
      FY3B_reader = load_reader(self.reader_configs)
      FY3B_file = FY3B_reader.select_files_from_pathnames(
          ["tf2018359214943.FY3B-L_VIRRX_L1B.HDF"]
      )
      assert 1 == len(FY3B_file)
      FY3B_reader.create_filehandlers(FY3B_file)
      # Make sure we have some files
      assert FY3B_reader.file_handlers
      self._fy3_helper(
          "FY3B", FY3B_reader, "milliWstts/m^2/cm^(-1)/steradian"
      )
  
imports: import os
  import unittest
  from unittest import mock
  import dask.array
  import numpy
  import xarray
  from satpy.tests.reader_tests.test_hdf5_utils import FakeHDF5FileHandler
label_desc: Use image node_id 5 for calling the TestVIRRL1BReader obj's underlying member method code with example usage: obj.test_fy3b_file() without return types