new_contents: import numpy as np
  from numpy.testing import assert_allclose
  
  import pytest
  
  from keras.preprocessing.sequence import (pad_sequences, make_sampling_table,
                                            skipgrams)
  
  
  def test_pad_sequences():
      a = [[1], [1, 2], [1, 2, 3]]
  
      # test padding
      b = pad_sequences(a, maxlen=3, padding='pre')
      assert_allclose(b, [[0, 0, 1], [0, 1, 2], [1, 2, 3]])
      b = pad_sequences(a, maxlen=3, padding='post')
      assert_allclose(b, [[1, 0, 0], [1, 2, 0], [1, 2, 3]])
  
      # test truncating
      b = pad_sequences(a, maxlen=2, truncating='pre')
      assert_allclose(b, [[0, 1], [1, 2], [2, 3]])
      b = pad_sequences(a, maxlen=2, truncating='post')
      assert_allclose(b, [[0, 1], [1, 2], [1, 2]])
  
      # test value
      b = pad_sequences(a, maxlen=3, value=1)
      assert_allclose(b, [[1, 1, 1], [1, 1, 2], [1, 2, 3]])
  
  
  def test_make_sampling_table():
      a = make_sampling_table(3)
      assert_allclose(a, np.asarray([0.00315225,  0.00315225,  0.00547597]),
                      rtol=.1)
  
  
  def test_skipgrams():
      # test with no window size and binary labels
      couples, labels = skipgrams(np.arange(3), vocabulary_size=3)
      for couple in couples:
          assert couple[0] in [0, 1, 2] and couple[1] in [0, 1, 2]
  
      # test window size and categorical labels
      couples, labels = skipgrams(np.arange(5), vocabulary_size=5, window_size=1,
                                  categorical=True)
      for couple in couples:
          assert couple[0] - couple[1] < 3
      for l in labels:
          assert len(l) == 2
  
      # test categorical laels
  
  
  
  if __name__ == '__main__':
      pytest.main([__file__])
  
subject: rename to and add more complete tests