code: def test_savitzky_golay():
      y = np.zeros(100)
      y[::2] = 1
      with pytest.warns(AstroMLDeprecationWarning):
          f = savitzky_golay(y, window_size=3, order=1)
      assert_allclose(f, (2 - y) / 3.0)
  
file_path: astroML/astroML/tests/test_filters.py
imports: import pytest
  import numpy
  from numpy.testing import assert_allclose
  from astroML.filters import savitzky_golay, wiener_filter
  from astroML.utils.exceptions import AstroMLDeprecationWarning
label_desc: Use image node_id 1 for calling a global function with example usage: test_savitzky_golay() without return types