code: def test_fista():
      """Test for fista operator"""
      a = T.tensor(np.random.rand(20, 10))
      true_res = T.tensor(np.random.rand(10, 1))
      b = T.dot(a, true_res)
      atb = T.dot(T.transpose(a), b)
      ata = T.dot(T.transpose(a), a)
      x_fista = fista(atb, ata, tol=10e-16, n_iter_max=5000)
      assert_array_almost_equal(true_res, x_fista, decimal=2)
  
imports: import numpy
  from ...None import backend
  from ..proximal import svd_thresholding, smoothness_prox, soft_thresholding, hals_nnls, fista, active_set_nnls, procrustes, hard_thresholding, soft_sparsity_prox, simplex_prox, normalized_sparsity_prox, monotonicity_prox, unimodality_prox, l2_prox, l2_square_prox, admm
  from ...testing import assert_, assert_array_equal, assert_array_almost_equal
  from tensorly import tensor_to_vec, truncated_svd
  import pytest
label_desc: Use image node_id 14 for calling a global function with example usage: test_fista() without return types