code: def testString(self):
      self.assertAllEqual(
          string_ops.as_string("hello, world!"), "hello, world!"
      )
      widened_string = self.evaluate(
          string_ops.as_string("hello, world!", width=20)
      )
      self.assertAllEqual(widened_string, "       hello, world!")
  
file_path: tensorflow/tensorflow/python/kernel_tests/strings_ops/as_string_op_test.py
imports: import numpy
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import string_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 7 for calling the AsStringOpTest obj's underlying member method code with example usage: obj.testString() without return types