code: def test_spilu(matrices):
      A_dense, A_sparse, b = matrices
      sparse_cls = type(A_sparse)
  
      lu = splin.spilu(A_sparse)
  
      assert isinstance(lu.L, sparse_cls)
      assert isinstance(lu.U, sparse_cls)
  
      z = lu.solve(A_sparse.todense())
      assert_allclose(z, np.eye(len(b)), atol=1e-3)
  
imports: import pytest
  import numpy
  import scipy.sparse
  import scipy.sparse.linalg
  from numpy.testing import assert_allclose
label_desc: Use image node_id 13 for calling a global function with example usage: test_spilu(matrices) without return types