code: def test_diff_append(n):
      x = cupy.arange(5) + 1
      a = da.from_array(x, chunks=2)
      assert_eq(da.diff(a, n, append=0), cupy.diff(x, n, append=0))
      assert_eq(da.diff(a, n, append=[0]), cupy.diff(x, n, append=[0]))
      assert_eq(
          da.diff(a, n, append=[-1, 0]), cupy.diff(x, n, append=[-1, 0])
      )
  
      x = cupy.arange(16).reshape(4, 4)
      a = da.from_array(x, chunks=2)
      assert_eq(
          da.diff(a, n, axis=1, append=0),
          cupy.diff(x, n, axis=1, append=0),
      )
      assert_eq(
          da.diff(a, n, axis=1, append=[[0], [0], [0], [0]]),
          cupy.diff(x, n, axis=1, append=[[0], [0], [0], [0]]),
      )
      assert_eq(
          da.diff(a, n, axis=0, append=0),
          cupy.diff(x, n, axis=0, append=0),
      )
      assert_eq(
          da.diff(a, n, axis=0, append=[[0, 0, 0, 0]]),
          cupy.diff(x, n, axis=0, append=[[0, 0, 0, 0]]),
      )
  
      if n > 0:
          with pytest.raises(ValueError):
              # When order is 0 the result is the icupyut array, it doesn't raise
              # an error
              da.diff(a, n, append=cupy.zeros((3, 3)))
  
file_path: dask/dask/array/tests/test_cupy_routines.py
imports: from __future__ import annotations
  import numpy
  import pytest
  from packaging.version import parse
  import dask.array
  from dask.array.utils import assert_eq, same_keys
label_desc: Use image node_id 5 for calling a global function with example usage: test_diff_append(n) without return types