class_docstr: A unittest class for testing the Carlini L2 attack.
class_docstr_tok: ["A","unittest","class","for","testing","the","Carlini","L2","attack","."]
docstr: Test the corner case when attack is failed.
  :return:
docstr_tok: ["Test","the","corner","case","when","attack","is","failed",".",":","return",":"]
code: def test_tensorflow_failure_attack_L2(self):
      """
      Test the corner case when attack is failed.
      :return:
      """
      x_test_original = self.x_test_mnist.copy()
  
      # Build TensorFlowClassifier
      tfc, sess = get_image_classifier_tf(from_logits=True)
  
      # Failure attack
      cl2m = CarliniL2Method(
          classifier=tfc,
          targeted=True,
          max_iter=0,
          binary_search_steps=0,
          learning_rate=0,
          initial_const=1,
          verbose=False,
      )
      params = {"y": random_targets(self.y_test_mnist, tfc.nb_classes)}
      x_test_adv = cl2m.generate(self.x_test_mnist, **params)
      self.assertLessEqual(np.amax(x_test_adv), 1.0)
      self.assertGreaterEqual(np.amin(x_test_adv), 0.0)
      np.testing.assert_array_almost_equal(
          self.x_test_mnist, x_test_adv, decimal=3
      )
  
      # Check that x_test has not been modified by attack and classifier
      self.assertAlmostEqual(
          float(np.max(np.abs(x_test_original - self.x_test_mnist))),
          0.0,
          delta=0.00001,
      )
  
      # Clean-up session
      if sess is not None:
          sess.close()
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import logging
  import unittest
  import numpy
  from art.attacks.evasion.carlini import CarliniL0Method, CarliniL2Method, CarliniLInfMethod
  from art.estimators.estimator import BaseEstimator
  from art.estimators.classification.classifier import ClassGradientsMixin
  from art.utils import random_targets
  from tests.utils import TestBase, master_seed
  from tests.utils import get_image_classifier_tf
  from tests.utils import get_image_classifier_pt
  from tests.attacks.utils import backend_test_classifier_type_check_fail
label_desc: Use image node_id 3 for calling the TestCarlini obj's underlying member method code with example usage: obj.test_tensorflow_failure_attack_L2() without return types