class_docstr: Test case. 
docstr: Test rolling window. 
docstr_tok: ["Test","rolling","window","."]
code: def test_rolling(self):
      """Test rolling window."""
      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)
  
file_path: delta/delta/data/feat/python_speech_features/test/test_sigproc.py
imports: import time
  import unittest
  import numpy
  import sigproc
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