code: def testUnknownIndices(self):
      input_array = [
          ["this", "is", "a", "test"],
          ["please", "do", "not", "panic"],
      ]
      truth_dim_zero = ["thisplease", "isdo", "anot", "testpanic"]
      truth_dim_one = ["thisisatest", "pleasedonotpanic"]
      truth_shape = None
      with self.cached_session():
          placeholder = array_ops.placeholder(
              dtypes.int32, name="placeholder"
          )
          reduced = string_ops.reduce_join(
              input_array, axis=placeholder
          )
          output_array_dim_zero = reduced.eval(
              feed_dict={placeholder.name: [0]}
          )
          output_array_dim_one = reduced.eval(
              feed_dict={placeholder.name: [1]}
          )
          self.assertAllEqualUnicode(
              truth_dim_zero, output_array_dim_zero
          )
          self.assertAllEqualUnicode(
              truth_dim_one, output_array_dim_one
          )
          self.assertAllEqual(truth_shape, reduced.get_shape())
  
imports: import itertools
  import numpy
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import string_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 10 for calling the ReduceJoinTest obj's underlying member method code with example usage: obj.testUnknownIndices() without return types