code: def test_timer_time_remaining(time_mock):
      """Test that the timer tracks the elapsed and remaining time correctly."""
      start_time = time.monotonic()
      duration = timedelta(seconds=10)
      time_mock.monotonic.return_value = start_time
      timer = Timer(duration=duration)
      assert timer.time_remaining() == duration.total_seconds()
      assert timer.time_elapsed() == 0
  
      # timer not started yet
      time_mock.monotonic.return_value = start_time + 60
      assert timer.start_time() is None
      assert timer.time_remaining() == 10
      assert timer.time_elapsed() == 0
  
      # start timer
      time_mock.monotonic.return_value = start_time
      timer.on_train_start(trainer=Mock(), pl_module=Mock())
      assert timer.start_time() == start_time
  
      # pretend time has elapsed
      elapsed = 3
      time_mock.monotonic.return_value = start_time + elapsed
      assert timer.start_time() == start_time
      assert round(timer.time_remaining()) == 7
      assert round(timer.time_elapsed()) == 3
  
imports: import logging
  import time
  from datetime import timedelta
  from unittest.mock import Mock, patch
  import pytest
  from lightning.pytorch import Trainer
  from lightning.pytorch.callbacks import ModelCheckpoint
  from lightning.pytorch.callbacks.timer import Timer
  from lightning.pytorch.demos.boring_classes import BoringModel
  from lightning.pytorch.utilities.exceptions import MisconfigurationException
  from tests_pytorch.helpers.runif import RunIf
label_desc: Use image node_id 4 for calling a global function with example usage: test_timer_time_remaining(time_mock) without return types