class_docstr: Tests for util functions.
code: def test_rolling_window_indices(self):
      # All valid.
      indices, mask = model._rolling_window_indices(3, 2, [3])
      self.assertAllEqual(indices, [[[0, 1], [1, 2], [2, 0]]])
      self.assertAllEqual(mask, [[True, True, True]])
      # One invalid.
      indices, mask = model._rolling_window_indices(3, 2, [2])
      self.assertAllEqual(indices, [[[0, 1], [1, 0], [0, 1]]])
      self.assertAllEqual(mask, [[True, True, False]])
      # All invalid.
      indices, mask = model._rolling_window_indices(3, 2, [0])
      self.assertAllEqual(indices, [[[0, 0], [0, 0], [0, 0]]])
      self.assertAllEqual(mask, [[False, False, False]])
      # size < rw_size.
      indices, mask = model._rolling_window_indices(2, 3, [2])
      self.assertAllEqual(indices, [[[0, 1, 0], [1, 0, 1]]])
      self.assertAllEqual(mask, [[True, True]])
      # batch_size = 2
      indices, mask = model._rolling_window_indices(3, 2, [3, 2])
      self.assertAllEqual(
          indices, [[[0, 1], [1, 2], [2, 0]], [[0, 1], [1, 0], [0, 1]]]
      )
      self.assertAllEqual(
          mask, [[True, True, True], [True, True, False]]
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  from absl.testing import parameterized
  import tensorflow
  from tensorflow import estimator
  from tensorflow_ranking.python import feature
  from tensorflow_ranking.python import head
  from tensorflow_ranking.python import losses
  from tensorflow_ranking.python import model
label_desc: Use image node_id 2 for calling the UtilsTest obj's underlying member method code with example usage: obj.test_rolling_window_indices() without return types