code: def test_rolling(self):
      x = np.arange(10)
      y = sigproc.rolling_window(x, window=4, step=3)
      y_expected = np.array([[0, 1, 2, 3], [3, 4, 5, 6], [6, 7, 8, 9]])
      y = np.testing.assert_array_equal(y, y_expected)
  
imports: from python_speech_features import sigproc
  import unittest
  import numpy
  import time
label_desc: Use image node_id 2 for calling the test_case obj's underlying member method code with example usage: obj.test_rolling() without return types