code: def test_connected_components():
      """Test the estimation of connected components"""
      toto = np.ones(shape)
      ddom = domain_from_binary_array(toto)
      assert_array_equal(
          ddom.connected_components(), np.zeros(ddom.size)
      )
  
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 10 for calling a global function with example usage: test_connected_components() without return types