code: def test_kronsum(self):
      cases = []
  
      cases.append(array([[0]]))
      cases.append(array([[-1]]))
      cases.append(array([[4]]))
      cases.append(array([[10]]))
      cases.append(array([[1, 2], [3, 4]]))
      cases.append(array([[0, 2], [5, 0]]))
      cases.append(array([[0, 2, -6], [8, 0, 14], [0, 3, 0]]))
      cases.append(array([[1, 0, 0], [0, 5, -1], [4, -2, 8]]))
  
      for a in cases:
          for b in cases:
              result = construct.kronsum(
                  csr_matrix(a), csr_matrix(b)
              ).todense()
              expected = np.kron(np.eye(len(b)), a) + np.kron(
                  b, np.eye(len(a))
              )
              assert_array_equal(result, expected)
  
imports: import numpy
  from numpy import array
  from numpy.testing import assert_equal, assert_, assert_array_equal, assert_array_almost_equal_nulp
  import pytest
  from pytest import raises
  from scipy._lib._testutils import check_free_memory
  from scipy._lib._util import check_random_state
  from scipy.sparse import csr_matrix, coo_matrix, construct
  from scipy.sparse.construct import rand
  from scipy.sparse.sputils import matrix
label_desc: Use image node_id 15 for calling the TestConstructUtils obj's underlying member method code with example usage: obj.test_kronsum() without return types