class_docstr: Test the normalize function.
class_docstr_tok: ["Test","the","normalize","function","."]
docstr: Test the std normalization.
docstr_tok: ["Test","the","std","normalization","."]
code: def test_std(self):
      """Test the std normalization."""
      # Zero-std case
      y = np.array([1])
      y_norm = normalize(y, "stats")
      assert_allclose(y_norm, y - 1)
  
      y = np.array([0, 0, 0])
      y_norm = normalize(y + 1, "stats")
      assert_allclose(y_norm, y)
  
      y = np.array([1, 3])[:, None]
      y_norm = normalize(y, "stats")
      assert_allclose(y_norm, np.array([[-1], [1]]))
  
      y = np.arange(5)
      y_norm = normalize(y, "stats")
      assert_allclose(y_norm, (y - y.mean()) / y.std())
  
imports: from __future__ import division
  import numpy
  import unittest
  from numpy.testing import assert_allclose
  from GPyOpt.core.errors import InvalidConfigError
  from GPyOpt.core.task.space import Design_space
  from GPyOpt.experiment_design import initial_design
  from GPyOpt.util.general import normalize
label_desc: Use image node_id 3 for calling the TestNormalization obj's underlying member method code with example usage: obj.test_std() without return types