code: def test_random(self):
      # the mean should be 0
      # the variance should be (2*stepsize)**2 / 12
      # note these tests are random, they will fail from time to time
      x = self.displace(self.x0)
      v = (2.0 * self.stepsize) ** 2 / 12
      assert_almost_equal(np.mean(x), 0.0, 1)
      assert_almost_equal(np.var(x), v, 1)
  
imports: import copy
  from numpy.testing import assert_almost_equal, assert_equal, assert_, assert_allclose
  import pytest
  from pytest import raises
  import numpy
  from numpy import cos, sin
  from scipy.optimize import basinhopping, OptimizeResult
  from scipy.optimize._basinhopping import Storage, RandomDisplacement, Metropolis, AdaptiveStepsize
label_desc: Use image node_id 2 for calling the Test_RandomDisplacement obj's underlying member method code with example usage: obj.test_random() without return types