code: def test_init(mock_exchange_class):
      exchange = mock_exchange_class.return_value
      exchange.options = ExchangeOptions()
      exchange.id = "fake_exchange_id"
      exchange.name = "bitfinex"
  
      wallets = [
          Wallet(exchange, 10000 * USD),
          Wallet(exchange, 0 * BTC),
      ]
      portfolio = Portfolio(USD, wallets)
  
      order = Order(
          step=0,
          exchange_pair=ExchangePair(exchange, USD / BTC),
          side=TradeSide.BUY,
          trade_type=TradeType.MARKET,
          quantity=5000 * USD,
          price=7000,
          portfolio=portfolio,
      )
  
      assert order
      assert order.id
      assert order.path_id
      assert order.step == 0
      assert order.quantity.instrument == USD
      assert order.remaining == order.quantity
      assert isinstance(order.pair, TradingPair)
      assert order.pair.base == USD
      assert order.pair.quote == BTC
  
imports: import re
  import unittest.mock
  from decimal import Decimal
  from tensortrade.oms.instruments import *
  from tensortrade.oms.orders import Order, OrderStatus, OrderSpec, TradeSide, TradeType
  from tensortrade.oms.orders.criteria import Stop
  from tensortrade.oms.exchanges import ExchangeOptions
  from tensortrade.oms.wallets import Wallet, Portfolio
label_desc: Use image node_id 1 for calling a global function with example usage: test_init(mock_exchange_class) without return types