code: def test_optimize_read_slicers():
      # Test function to optimize read slicers
      assert optimize_read_slicers((1,), (10,), 4, _never) == ((1,), ())
      assert optimize_read_slicers(
          (slice(None),), (10,), 4, _never
      ) == (
          (slice(None),),
          (slice(None),),
      )
      assert optimize_read_slicers((slice(9),), (10,), 4, _never) == (
          (slice(0, 9, 1),),
          (slice(None),),
      )
      # optimize cannot update a continuous to a full if last
      assert optimize_read_slicers((slice(9),), (10,), 4, _always) == (
          (slice(0, 9, 1),),
          (slice(None),),
      )
      # optimize can update non-contiguous to continuous even if last
      # not optimizing
      assert optimize_read_slicers(
          (slice(0, 9, 2),), (10,), 4, _never
      ) == (
          (slice(0, 9, 2),),
          (slice(None),),
      )
      # optimizing
      assert optimize_read_slicers(
          (slice(0, 9, 2),), (10,), 4, _always
      ) == (
          (slice(0, 9, 1),),
          (slice(None, None, 2),),
      )
      # Optimize does nothing for integer when last
      assert optimize_read_slicers((1,), (10,), 4, _always) == (
          (1,),
          (),
      )
      # 2D
      assert optimize_read_slicers(
          (slice(None), slice(None)), (10, 6), 4, _never
      ) == (
          (slice(None), slice(None)),
          (slice(None), slice(None)),
      )
      assert optimize_read_slicers(
          (slice(None), 1), (10, 6), 4, _never
      ) == (
          (slice(None), 1),
          (slice(None),),
      )
      assert optimize_read_slicers(
          (1, slice(None)), (10, 6), 4, _never
      ) == (
          (1, slice(None)),
          (slice(None),),
      )
      # Not optimizing a partial slice
      assert optimize_read_slicers(
          (slice(9), slice(None)), (10, 6), 4, _never
      ) == (
          (slice(0, 9, 1), slice(None)),
          (slice(None), slice(None)),
      )
      # Optimizing a partial slice
      assert optimize_read_slicers(
          (slice(9), slice(None)), (10, 6), 4, _always
      ) == (
          (slice(None), slice(None)),
          (slice(0, 9, 1), slice(None)),
      )
      # Optimize cannot update a continuous to a full if last
      assert optimize_read_slicers(
          (slice(None), slice(5)), (10, 6), 4, _always
      ) == (
          (slice(None), slice(0, 5, 1)),
          (slice(None), slice(None)),
      )
      # optimize can update non-contiguous to full if not last
      # not optimizing
      assert optimize_read_slicers(
          (slice(0, 9, 3), slice(None)), (10, 6), 4, _never
      ) == (
          (slice(0, 9, 3), slice(None)),
          (slice(None), slice(None)),
      )
      # optimizing full
      assert optimize_read_slicers(
          (slice(0, 9, 3), slice(None)), (10, 6), 4, _always
      ) == (
          (slice(None), slice(None)),
          (slice(0, 9, 3), slice(None)),
      )
      # optimizing partial
      assert optimize_read_slicers(
          (slice(0, 9, 3), slice(None)), (10, 6), 4, _partial
      ) == (
          (slice(0, 9, 1), slice(None)),
          (slice(None, None, 3), slice(None)),
      )
      # optimize can update non-contiguous to continuous even if last
      # not optimizing
      assert optimize_read_slicers(
          (slice(None), slice(0, 5, 2)), (10, 6), 4, _never
      ) == (
          (slice(None), slice(0, 5, 2)),
          (slice(None), slice(None)),
      )
      # optimizing
      assert optimize_read_slicers(
          (slice(None), slice(0, 5, 2)), (10, 6), 4, _always
      ) == (
          (slice(None), slice(0, 5, 1)),
          (slice(None), slice(None, None, 2)),
      )
      # Optimize does nothing for integer when last
      assert optimize_read_slicers(
          (slice(None), 1), (10, 6), 4, _always
      ) == (
          (slice(None), 1),
          (slice(None),),
      )
      # Check gap threshold with 3D
      _depends0 = partial(threshold_heuristic, skip_thresh=10 * 4 - 1)
      _depends1 = partial(threshold_heuristic, skip_thresh=10 * 4)
      assert optimize_read_slicers(
          (slice(9), slice(None), slice(None)), (10, 6, 2), 4, _depends0
      ) == (
          (slice(None), slice(None), slice(None)),
          (slice(0, 9, 1), slice(None), slice(None)),
      )
      assert optimize_read_slicers(
          (slice(None), slice(5), slice(None)), (10, 6, 2), 4, _depends0
      ) == (
          (slice(None), slice(0, 5, 1), slice(None)),
          (slice(None), slice(None), slice(None)),
      )
      assert optimize_read_slicers(
          (slice(None), slice(5), slice(None)), (10, 6, 2), 4, _depends1
      ) == (
          (slice(None), slice(None), slice(None)),
          (slice(None), slice(0, 5, 1), slice(None)),
      )
      # Check longs as integer slices
      sn = slice(None)
      assert optimize_read_slicers(
          (1, 2, 3), (2, 3, 4), 4, _always
      ) == ((sn, sn, 3), (1, 2))
  
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 14 for calling a global function with example usage: test_optimize_read_slicers() without return types