text: import cocos.device
  import cocos.numerics as cn
  import numpy as np
  
  
  def test_diff():
      cocos.device.init()
  
      if cocos.device.is_dbl_supported():
          A_numpy = np.random.randn(1000, 1000)
          A_cocos = cn.array(A_numpy)
  
          # # using numpy
          # mean_numpy = np.mean(A_numpy)
          #
          # # using Cocos
  
          # mean_cocos = cn.mean(A_cocos)
  
          # conduct tests
  
          # tests sum
          for n in range(1, 10):
              assert np.allclose(np.diff(A_numpy, n=n),
                                 cn.diff(A_cocos, n=n))
  
              assert np.allclose(np.diff(A_numpy, n=n, axis=0),
                                 cn.diff(A_cocos, n=n, axis=0))
  
              assert np.allclose(np.diff(A_numpy, n=n, axis=1),
                                 cn.diff(A_cocos, n=n, axis=1))
  