code: def testNSteprewardum(self):
      memory = circular_replay_buffer.ReplayBuffer(
          stack_size=STACK_SIZE,
          replay_capacity=10,
          batch_size=BATCH_SIZE,
          update_horizon=5,
          gamma=1.0,
      )
  
      for i in range(50):
          memory.add(
              observation=np.full(
                  OBSERVATION_SHAPE, i, dtype=OBS_DTYPE
              ),
              action=0,
              reward=2.0,
              terminal=0,
          )
  
      for _i in range(100):
          batch = memory.sample_transition_batch()
          # Make sure the total reward is reward per step x update_horizon.
          self.assertEqual(batch[2][0], 10.0)
  
imports: import tempfile
  import unittest
  import numpy
  import numpy.testing
  import torch
  from reagent.replay_memory import circular_replay_buffer
label_desc: Use image node_id 7 for calling the ReplayBufferTest obj's underlying member method code with example usage: obj.testNSteprewardum() without return types