code: def test_smatrix_1d():
      """Test the 1-d topological domain"""
      idx = generate_dataset(shape[:1])
      sm = smatrix_from_nd_idx(idx, nn=0)
      assert sm.data.size == 2 * shape[0] - 2
  
imports: import nibabel.gifti
  import numpy
  from nibabel import Nifti1Image
  from numpy.testing import assert_almost_equal, assert_array_equal
  from ..discrete_domain import domain_from_binary_array, domain_from_image, domain_from_mesh, grid_domain_from_binary_array, grid_domain_from_image, grid_domain_from_shape, smatrix_from_3d_array, smatrix_from_nd_array, smatrix_from_nd_idx
label_desc: Use image node_id 2 for calling a global function with example usage: test_smatrix_1d() without return types