new_contents: import asyncio
  import logging
  import os
  import unittest
  from datetime import datetime
  
  from integration_tests.env_variable_names import \
      SLACK_SDK_TEST_BOT_TOKEN, \
      SLACK_SDK_TEST_WEB_TEST_CHANNEL_ID
  from integration_tests.helpers import async_test
  from slack import WebClient
  from slack.web.classes.objects import DateLink
  
  
  class TestWebClient(unittest.TestCase):
      """Runs integration tests with real Slack API
  
      https://github.com/slackapi/python-slackclient/issues/672
      """
  
      def setUp(self):
          if not hasattr(self, "logger"):
              self.logger = logging.getLogger(__name__)
              self.bot_token = os.environ[SLACK_SDK_TEST_BOT_TOKEN]
              self.sync_client: WebClient = WebClient(
                  token=self.bot_token,
                  run_async=False,
                  loop=asyncio.new_event_loop())
              self.async_client: WebClient = WebClient(token=self.bot_token, run_async=True)
              self.channel_id = os.environ[SLACK_SDK_TEST_WEB_TEST_CHANNEL_ID]
  
      def tearDown(self):
          pass
  
      def test_date_link(self):
          client = self.sync_client
          link = DateLink(
              date=datetime.now(),
              date_format="{date_long} {time}",
              fallback="fallback string",
              link="https://www.example.com"
          )
          message=f"Here is a date link: {link}"
          response = client.chat_postMessage(channel=self.channel_id, text=message)
          self.assertIsNotNone(response)
          self.assertRegexpMatches(response["message"]["text"], r"Here is a date link: <!date^\d+^{date_long} {time}^https://www.example.com|fallback string>")
  
      @async_test
      async def test_date_link_async(self):
          client = self.async_client
          link = DateLink(
              date=datetime.now(),
              date_format="{date_long} {time}",
              fallback="fallback string",
              link="https://www.example.com"
          )
          message=f"Here is a date link: {link}"
          response = await client.chat_postMessage(channel=self.channel_id, text=message)
          self.assertIsNotNone(response)
          self.assertRegexpMatches(response["message"]["text"], r"Here is a date link: <!date^\d+^{date_long} {time}^https://www.example.com|fallback string>")
  
subject: Add an integration test for #677