old_contents: import asyncio
  from unittest.mock import Mock
  
  from azure.core.credentials import AccessToken
  from devtools_testutils import AzureMgmtTestCase
  
  class AzureMgmtAsyncTestCase(AzureMgmtTestCase):
  
      def setUp(self):
          super(AzureMgmtAsyncTestCase, self).setUp()
  
      @property
      def event_loop(self):
          return asyncio.get_event_loop()
  
      def create_mgmt_aio_client(self, client, **kwargs):
          if self.is_live:
              from azure.identity.aio import DefaultAzureCredential
              credential = DefaultAzureCredential()
          else:
              credential = Mock(get_token=asyncio.coroutine(lambda _: AccessToken("fake-token", 0)))
          return client(
              credential=credential,
              subscription_id=self.settings.SUBSCRIPTION_ID
          )
  
      def to_list(self, ait):
          async def lst():
              result = []
              async for item in ait:
                  result.append(item)
              return result
          return self.event_loop.run_until_complete(lst())
  
new_contents: import asyncio
  from unittest.mock import Mock
  
  from azure.core.credentials import AccessToken
  from devtools_testutils import AzureMgmtTestCase
  
  class AzureMgmtAsyncTestCase(AzureMgmtTestCase):
  
      def setUp(self):
          super(AzureMgmtAsyncTestCase, self).setUp()
  
      @property
      def event_loop(self):
          return asyncio.get_event_loop()
  
      def mock_completed_future(self, result=None):
          future = asyncio.Future()
          future.set_result = result
          return future
  
      def create_mgmt_aio_client(self, client, **kwargs):
          if self.is_live:
              from azure.identity.aio import DefaultAzureCredential
              credential = DefaultAzureCredential()
          else:
              credential = Mock(get_token=lambda _: self.mock_completed_future(AccessToken("fake-token", 0)))
          return client(
              credential=credential,
              subscription_id=self.settings.SUBSCRIPTION_ID
          )
  
      def to_list(self, ait):
          async def lst():
              result = []
              async for item in ait:
                  result.append(item)
              return result
          return self.event_loop.run_until_complete(lst())
  
subject: Fix eventhub test (#27622)