code: def test_on_dask_array():
      """Test the `on_dask_array` decorator."""
  
      def func(dask_array):
          if not isinstance(dask_array, da.core.Array):
              pytest.fail("Array is not a dask array")
          return dask_array
  
      dask_func = on_dask_array(func)
      arr = xr.DataArray(
          da.zeros((3, 10, 10), dtype=int, chunks=5),
          dims=["bands", "y", "x"],
      )
      res = dask_func(arr)
      assert res.shape == arr.shape
  
imports: import contextlib
  import os
  from tempfile import NamedTemporaryFile
  from unittest import mock
  import dask.array
  import numpy
  import pytest
  import xarray
  from satpy.enhancements import create_colormap, on_dask_array, on_separate_bands, using_map_blocks
label_desc: Use image node_id 8 for calling a global function with example usage: test_on_dask_array() and returns: dask_array