code: def test_default_header(self):
      # Check default header is as expected
      arr = np.arange(24, dtype=np.int16).reshape((2, 3, 4))
      img = self.image_class(arr, None)
      hdr = self.image_class.header_class()
      hdr.set_data_shape(arr.shape)
      hdr.set_data_dtype(arr.dtype)
      hdr.set_data_offset(0)
      hdr.set_slope_inter(np.nan, np.nan)
      assert img.header == hdr
  
imports: import itertools
  import logging
  import os
  import pickle
  import re
  from io import BytesIO, StringIO
  import numpy
  import pytest
  from numpy.testing import assert_array_almost_equal, assert_array_equal
  from ..None import imageglobals
  from ..analyze import AnalyzeHeader, AnalyzeImage
  from ..arraywriters import WriterError
  from ..casting import sctypes_aliases
  from ..nifti1 import Nifti1Header
  from ..optpkg import optional_package
  from ..spatialimages import HeaderDataError, HeaderTypeError, supported_np_types
  from ..testing import assert_dt_equal, bytesio_filemap, bytesio_round_trip, data_path, suppress_warnings
  from ..tmpdirs import InTemporaryDirectory
  from .None import test_spatialimages
  from .None import test_wrapstruct
label_desc: Use image node_id 2 for calling the TestAnalyzeImage obj's underlying member method code with example usage: obj.test_default_header() without return types