code: def test_nmf_n_components_default_value_warning():
      rng = np.random.RandomState(0)
      X = rng.random_sample((6, 5))
      H = rng.random_sample((2, 5))
      with pytest.warns(
          FutureWarning,
          match="The default value of `n_components` will change from",
      ):
          non_negative_factorization(X, H=H)
  
imports: import re
  import sys
  import warnings
  from io import StringIO
  import numpy
  import pytest
  from scipy import linalg
  from sklearn.base import clone
  from sklearn.decomposition import NMF, MiniBatchNMF, non_negative_factorization
  from sklearn.decomposition import _nmf
  from sklearn.exceptions import ConvergenceWarning
  from sklearn.utils._testing import assert_allclose, assert_almost_equal, assert_array_almost_equal, assert_array_equal, ignore_warnings
  from sklearn.utils.extmath import squared_norm
  from sklearn.utils.fixes import CSC_CONTAINERS, CSR_CONTAINERS
label_desc: Use image node_id 38 for calling a global function with example usage: test_nmf_n_components_default_value_warning() without return types