code: def test_van_der_corput():
      x = _van_der_corput_samples(range(12), number_base=10)
      y = [0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.01, 0.11]
      assert_array_equal(x, y)
  
      x = _van_der_corput_samples(range(9), number_base=2)
      y = [0.0, 0.5, 0.25, 0.75, 0.125, 0.625, 0.375, 0.875, 0.0625]
      assert_array_equal(x, y)
  
imports: import pytest
  import numbers
  import numpy
  import os
  import yaml
  from tempfile import NamedTemporaryFile
  from numpy.testing import assert_array_almost_equal
  from numpy.testing import assert_almost_equal
  from numpy.testing import assert_array_equal
  from numpy.testing import assert_equal
  from numpy.testing import assert_raises
  from scipy import spatial
  from skopt import Optimizer
  from skopt.space import Space
  from skopt.space import Real
  from skopt.space import Integer
  from skopt.space import Categorical
  from skopt.space import check_dimension
  from skopt.sampler.sobol import _bit_lo0, _bit_hi1
  from skopt.sampler.halton import _van_der_corput_samples, _create_primes
  from skopt.sampler import Hammersly, Halton, Lhs, Sobol, Grid
  from skopt.sampler import InitialPointGenerator
  from skopt.sampler.grid import _create_uniform_grid_include_border
  from skopt.sampler.grid import _create_uniform_grid_exclude_border
  from skopt.sampler.grid import _quadrature_combine
  from skopt.sampler.grid import _create_uniform_grid_only_border
  from skopt.utils import cook_initial_point_generator
label_desc: Use image node_id 9 for calling a global function with example usage: test_van_der_corput() without return types