code: def test_injects_string_initialized_reward_scheme(self):
      with TradingContext(self.config):
          reward_scheme = rewards.get("simple")
  
          assert reward_scheme.registered_name == "rewards"
          assert hasattr(reward_scheme.context, "size")
          assert reward_scheme.context.size == 0
          assert reward_scheme.context["size"] == 0
  
file_path: tensortrade/tests/tensortrade/unit/env/default/test_rewards.py
imports: import pytest
  import numpy
  import pandas
  from collections import OrderedDict
  import tensortrade.env.default.rewards
  from tensortrade.core import TradingContext
  from tensortrade.oms.wallets import Portfolio
  from tensortrade.oms.instruments import USD
label_desc: Use image node_id 3 for calling the TestTensorTradeRewardScheme obj's underlying member method code with example usage: obj.test_injects_string_initialized_reward_scheme() without return types