code: def test_rank_one(self):
      input_array = [b"this", b"is", b"a", b"test"]
      truth = b"thisisatest"
      truth_shape = []
      with self.cached_session():
          output = ragged_string_ops.reduce_join(
              inputs=input_array, axis=-1, keepdims=False, separator=""
          )
          output_array = self.evaluate(output)
      self.assertAllEqual(truth, output_array)
      self.assertAllEqual(truth_shape, output.get_shape())
  
file_path: tensorflow-upstream/tensorflow/python/ops/ragged/strings_reduce_join_op_test.py
imports: from absl.testing import parameterized
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops.ragged import ragged_factory_ops
  from tensorflow.python.ops.ragged import ragged_string_ops
  from tensorflow.python.platform import googletest
label_desc: Use image node_id 1 for calling the StringsReduceJoinOpTest obj's underlying member method code with example usage: obj.test_rank_one() without return types