code: def testEnvironmentDiscoveryUrl(self):
      os.environ[
          "TPU_API_DISCOVERY_URL"
      ] = "https://{api}.internal/{apiVersion}"
      self.assertEqual(
          "https://{api}.internal/{apiVersion}",
          (client._environment_discovery_url()),
      )
  
imports: import datetime
  import json
  import os
  import time
  import urllib
  from absl import flags
  from tensorflow.python.platform import test
  from tensorflow.python.tpu.client import client
label_desc: Use image node_id 5 for calling the CloudTpuClientTest obj's underlying member method code with example usage: obj.testEnvironmentDiscoveryUrl() without return types