code: def test_as_volume_image():
      """Test casting VolumeGrid to VolumeImg"""
      N = 10
      v2w_mapping = Transform("voxels", "world2", id, id)
      data = np.random.random((N, N, N))
      img1 = VolumeGrid(
          data=data,
          transform=v2w_mapping,
      )
      img2 = img1.as_volume_img()
  
      # Check that passing in the wrong shape raises an error
      pytest.raises(ValueError, img1.as_volume_img, None, (10, 10))
  
file_path: nipy/nipy/labs/datasets/volumes/tests/test_volume_grid.py
imports: import copy
  import numpy
  import pytest
  from ...transforms.transform import CompositionError, Transform
  from ..volume_grid import VolumeGrid
  from ..volume_img import VolumeImg
label_desc: Use image node_id 8 for calling a global function with example usage: test_as_volume_image() without return types