docstr: Make sure that torch.cuda.synchronize() is called when GPU is present.
docstr_tok: ["Make","sure","that","torch.cuda.synchronize","(",")","is","called","when","GPU","is","present","."]
code: def test_timer_synchronize(self, mock_synchornize: Mock) -> None:
      """Make sure that torch.cuda.synchronize() is called when GPU is present."""
  
      start_event = torch.cuda.Event(enable_timing=True)
      end_event = torch.cuda.Event(enable_timing=True)
      timer = Timer()
  
      # Do not explicitly call synchronize, timer must call it for test to pass.
  
      with timer.time("action_1"):
          start_event.record()
          time.sleep(0.5)
          end_event.record()
  
      self.assertEqual(mock_synchornize.call_count, 2)
  
imports: import os
  import time
  import unittest
  from datetime import timedelta
  from random import random
  from unittest import mock
  from unittest.mock import Mock, patch
  import torch
  import torch.distributed
  from pyre_extensions import none_throws
  from torchtnt.utils.test_utils import skip_if_not_distributed, skip_if_not_gpu, spawn_multi_process
  from torchtnt.utils.timer import BoundedTimer, FullSyncPeriodicTimer, get_durations_histogram, get_recorded_durations_table, get_synced_durations_histogram, get_timer_summary, log_elapsed_time, logger, Timer
label_desc: Use image node_id 5 for calling the TimerTest obj's underlying member method code with example usage: obj.test_timer_synchronize(mock_synchornize) without return types