code: def test_unreachable_accuracy():
      assert_array_almost_equal(
          orthogonal_mp(X, y, tol=0),
          orthogonal_mp(X, y, n_nonzero_coefs=n_features),
      )
      warning_message = (
          "Orthogonal matching pursuit ended prematurely "
          "due to linear dependence in the dictionary. "
          "The requested precision might not have been met."
      )
      with pytest.warns(RuntimeWarning, match=warning_message):
          assert_array_almost_equal(
              orthogonal_mp(X, y, tol=0, precompute=True),
              orthogonal_mp(
                  X, y, precompute=True, n_nonzero_coefs=n_features
              ),
          )
  
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 7 for calling a global function with example usage: test_unreachable_accuracy() without return types