code: def __test_impl(self, action):
      order = backtesting.MarketOrder(
          action,
          BaseTestCase.TestInstrument,
          5,
          False,
          broker.IntegerTraits(),
      )
      price = 10
  
      slippedPrice = self.slippage.calculatePrice(
          order,
          price,
          order.getQuantity(),
          self.barsBuilder.nextBar(10, 11, 9, 10, volume=100),
          0,
      )
      self.assertEqual(price, slippedPrice)
  
      slippedPrice = self.slippage.calculatePrice(
          order,
          price,
          order.getQuantity(),
          self.barsBuilder.nextBar(10, 11, 9, 10, volume=100),
          20,
      )
      self.assertEqual(slippedPrice, price)
  
imports: import unittest
  from .None import broker_backtesting_test
  from pyalgotrade import broker
  from pyalgotrade.broker import slippage
  from pyalgotrade.broker import backtesting
  from pyalgotrade import bar
label_desc: Use image node_id 2 for calling the NoSlippageTestCase obj's underlying member method code with example usage: obj.__test_impl(action) without return types