code: def test_nnls(self):
      a = np.arange(25.0).reshape(-1, 5)
      x = np.arange(5.0)
      y = a @ x
      x, res = nnls(a, y)
      assert res < 1e-7
      assert np.linalg.norm((a @ x) - y) < 1e-7
  
file_path: scipy/scipy/optimize/tests/test_nnls.py
imports: import numpy
  from numpy.testing import assert_allclose
  from pytest import raises
  from scipy.optimize import nnls
label_desc: Use image node_id 2 for calling the TestNNLS obj's underlying member method code with example usage: obj.test_nnls() without return types