code: def test_no_atoms():
      y_empty = np.zeros_like(y)
      Xy_empty = np.dot(X.T, y_empty)
      gamma_empty = ignore_warnings(orthogonal_mp)(
          X, y_empty, n_nonzero_coefs=1
      )
      gamma_empty_gram = ignore_warnings(orthogonal_mp)(
          G, Xy_empty, n_nonzero_coefs=1
      )
      assert np.all(gamma_empty == 0)
      assert np.all(gamma_empty_gram == 0)
  
imports: import numpy
  import pytest
  from sklearn.datasets import make_sparse_coded_signal
  from sklearn.linear_model import LinearRegression, OrthogonalMatchingPursuit, OrthogonalMatchingPursuitCV, orthogonal_mp, orthogonal_mp_gram
  from sklearn.utils import check_random_state
  from sklearn.utils._testing import assert_allclose, assert_array_almost_equal, assert_array_equal, ignore_warnings
label_desc: Use image node_id 14 for calling a global function with example usage: test_no_atoms() without return types