code: def test_fileslice():
      shapes = (15, 16, 17)
      for n_dim in range(1, len(shapes) + 1):
          shape = shapes[:n_dim]
          arr = np.arange(np.prod(shape)).reshape(shape)
          for order in "FC":
              for offset in (0, 20):
                  fobj = BytesIO()
                  fobj.write(b"\0" * offset)
                  fobj.write(arr.tobytes(order=order))
                  for sliceobj in slicer_samples(shape):
                      _check_slicer(sliceobj, arr, fobj, offset, order)
  
imports: import time
  from functools import partial
  from io import BytesIO
  from itertools import product
  from threading import Lock, Thread
  import numpy
  import pytest
  from numpy.testing import assert_array_equal
  from ..fileslice import _positive_slice, _simple_fileslice, calc_slicedefs, canonical_slicers, fileslice, fill_slicer, is_fancy, optimize_read_slicers, optimize_slicer, predict_shape, read_segments, slice2len, slice2outax, slicers2segments, strided_scalar, threshold_heuristic
label_desc: Use image node_id 24 for calling a global function with example usage: test_fileslice() without return types