code: def test_get_ondemand_prices(self):
      wm = self.get_worker_manager()
      prices = wm._get_ondemand_prices(["c4.large", "p2.xlarge"])
  
      expected_prices = {"c4.large": 0.1, "p2.xlarge": 0.9}
      self.assertEquals(prices, expected_prices)
  
imports: import unittest
  import os
  import uuid
  from studio.gcloud_worker import GCloudWorkerManager
  from studio.ec2cloud_worker import EC2WorkerManager
  from local_worker_test import stubtest_worker
  from timeout_decorator import timeout
  from studio.extra_util import has_aws_credentials
  from env_detect import on_gcp, on_aws
label_desc: Use image node_id 4 for calling the EC2WorkerTest obj's underlying member method code with example usage: obj.test_get_ondemand_prices() without return types