class_docstr: A unittest class for testing the ElasticNet attack.
class_docstr_tok: ["A","unittest","class","for","testing","the","ElasticNet","attack","."]
docstr: Test the corner case when attack fails.
  :return:
docstr_tok: ["Test","the","corner","case","when","attack","fails",".",":","return",":"]
code: def test_2_tensorflow_failure_attack(self):
      """
      Test the corner case when attack fails.
      :return:
      """
      # Build TensorFlowClassifier
      tfc, sess = get_image_classifier_tf()
  
      # Failure attack
      ead = ElasticNet(
          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 = ead.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_almost_equal(self.x_test_mnist, x_test_adv, 3)
  
      # 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 keras.backend
  import numpy
  from art.attacks.evasion.elastic_net import ElasticNet
  from art.estimators.estimator import BaseEstimator
  from art.estimators.classification.classifier import ClassGradientsMixin
  from art.estimators.classification.keras import KerasClassifier
  from art.utils import random_targets, to_categorical
  from tests.attacks.utils import backend_test_classifier_type_check_fail
  from tests.utils import TestBase, get_image_classifier_kr, get_image_classifier_pt, get_image_classifier_tf, get_tabular_classifier_kr, get_tabular_classifier_pt, get_tabular_classifier_tf, master_seed
label_desc: Use image node_id 3 for calling the TestElasticNet obj's underlying member method code with example usage: obj.test_2_tensorflow_failure_attack() without return types