code: def test_sum_without_data(ctx_factory):
      from pytest import importorskip
  
      importorskip("mako")
  
      context = ctx_factory()
      queue = cl.CommandQueue(context)
  
      n = 2000
  
      from pyopencl.reduction import ReductionKernel
  
      red = ReductionKernel(
          context,
          np.int32,
          neutral="0",
          reduce_expr="a+b",
          map_expr="i",
          arguments=[],
      )
  
      result_dev = red(range=slice(n), queue=queue).get()
      result_ref = n * (n - 1) // 2
  
      assert result_dev == result_ref
  
imports: import numpy
  import numpy.linalg
  import sys
  from pytools import memoize
  from test_array import general_clrand
  import pytest
  import pyopencl
  import pyopencl.array
  from pyopencl.tools import pytest_generate_tests_for_pyopencl
  from pyopencl.characterize import has_double_support, has_struct_arg_count_bug
  from pyopencl.scan import InclusiveScanKernel, ExclusiveScanKernel, GenericScanKernel, GenericDebugScanKernel
  from pyopencl.characterize import get_pocl_version
label_desc: Use image node_id 11 for calling a global function with example usage: test_sum_without_data(ctx_factory) without return types