code: def testWordCountEmpty(self):
      with tf.compat.v1.Graph().as_default():
          output_tensor = mappers.word_count(
              tf.compat.v1.string_split(tf.constant([""]))
          )
          with tf.compat.v1.Session():
              output = output_tensor.eval()
              self.assertEqual(1, len(output))
              self.assertEqual(0, sum(output))
  
imports: import numpy
  import tensorflow
  from tensorflow_transform import mappers
  from tensorflow_transform import test_case
label_desc: Use image node_id 15 for calling the MappersTest obj's underlying member method code with example usage: obj.testWordCountEmpty() without return types