code: def testImageGenerator(self):
      # 2 random images
      np.random.seed(1111)  # To avoid any flakiness.
      image1 = np.random.randint(0, 255, size=(10, 12, 3))
      image2 = np.random.randint(0, 255, size=(10, 12, 3))
      # Call image generator on the 2 images with labels [1, 2].
      encoded_imgs, labels = [], []
      for dictionary in image_utils.image_generator(
          [image1, image2], [1, 2]
      ):
          self.assertEqual(
              sorted(list(dictionary)),
              [
                  "image/class/label",
                  "image/encoded",
                  "image/format",
                  "image/height",
                  "image/width",
              ],
          )
          self.assertEqual(dictionary["image/format"], ["png"])
          self.assertEqual(dictionary["image/height"], [12])
          self.assertEqual(dictionary["image/width"], [10])
          encoded_imgs.append(dictionary["image/encoded"])
          labels.append(dictionary["image/class/label"])
  
      # Check that the result labels match the inputs.
      self.assertEqual(len(labels), 2)
      self.assertEqual(labels[0], [1])
      self.assertEqual(labels[1], [2])
  
      # Decode images and check that they match the inputs.
      self.assertEqual(len(encoded_imgs), 2)
      image_t = tf.placeholder(dtype=tf.string)
      decoded_png_t = tf.image.decode_png(image_t)
      with self.test_session() as sess:
          encoded_img1 = encoded_imgs[0]
          self.assertEqual(len(encoded_img1), 1)
          decoded1 = sess.run(
              decoded_png_t, feed_dict={image_t: encoded_img1[0]}
          )
          self.assertAllClose(decoded1, image1)
          encoded_img2 = encoded_imgs[1]
          self.assertEqual(len(encoded_img2), 1)
          decoded2 = sess.run(
              decoded_png_t, feed_dict={image_t: encoded_img2[0]}
          )
          self.assertAllClose(decoded2, image2)
  
file_path: tensor2tensor/tensor2tensor/data_generators/image_utils_test.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import numpy
  from tensor2tensor.data_generators import image_utils
  from tensor2tensor.utils import decoding
  import tensorflow.compat.v1
label_desc: Use image node_id 2 for calling the ImageTest obj's underlying member method code with example usage: obj.testImageGenerator() without return types