code: def test_add_trend_prepend(rng):
      n = 10
      x = rng.randn(n, 1)
      trend_1 = add_trend(x, trend="ct", prepend=True)
      trend_2 = add_trend(x, trend="ct", prepend=False)
      assert_equal(trend_1[:, :2], trend_2[:, 1:])
  
imports: import numpy
  from numpy.random import RandomState
  from numpy.testing import assert_array_almost_equal, assert_array_equal, assert_equal
  import pandas
  from pandas.testing import assert_frame_equal
  import pytest
  from arch.utility.timeseries import ColumnNameConflict, add_trend
label_desc: Use image node_id 3 for calling a global function with example usage: test_add_trend_prepend(rng) without return types