docstr: Test that the logging happens as expected and the loss and lr values are
  correct.
docstr_tok: ["Test","that","the","logging","happens","as","expected","and","the","loss","and","lr","values","are","correct","."]
code: def test_logging(self, mock_get_rank: mock.MagicMock) -> None:
      """
      Test that the logging happens as expected and the loss and lr values are
      correct.
      """
      rank = 5
      mock_get_rank.return_value = rank
  
      # set up the task and state
      config = get_test_task_config()
      config["dataset"]["train"]["batchsize_per_replica"] = 2
      config["dataset"]["test"]["batchsize_per_replica"] = 5
      task = build_task(config)
      task.prepare()
      task.on_start()
      task.on_phase_start()
  
      losses = [1.2, 2.3, 3.4, 4.5]
  
      task.phase_idx = 0
  
      for log_freq in [5, None]:
          # create a loss lr meter hook
          loss_lr_meter_hook = LossLrMeterLoggingHook(log_freq=log_freq)
  
          # check that _log_loss_lr_meters() is called after on_step() every
          # log_freq batches and after on_phase_end()
          with mock.patch.object(
              loss_lr_meter_hook, "_log_loss_lr_meters"
          ) as mock_fn:
              num_batches = 20
  
              for i in range(num_batches):
                  task.losses = list(range(i))
                  loss_lr_meter_hook.on_step(task)
                  if log_freq is not None and i and i % log_freq == 0:
                      mock_fn.assert_called()
                      mock_fn.reset_mock()
                      continue
                  mock_fn.assert_not_called()
  
              loss_lr_meter_hook.on_phase_end(task)
              mock_fn.assert_called()
  
          # test _log_loss_lr_meters()
          task.losses = losses
  
          with self.assertLogs():
              loss_lr_meter_hook._log_loss_lr_meters(task)
  
          task.phase_idx += 1
  
file_path: ClassyVision/test/hooks_loss_lr_meter_logging_hook_test.py
imports: import copy
  import unittest
  import unittest.mock
  from itertools import product
  from classy_vision.hooks import ClassyHook, LossLrMeterLoggingHook
  from classy_vision.optim.param_scheduler import ClassyParamScheduler, UpdateInterval
  from classy_vision.tasks import build_task, ClassyTask
  from classy_vision.trainer import LocalTrainer
  from test.generic.config_utils import get_test_mlp_task_config, get_test_task_config
  from test.generic.hook_test_utils import HookTestBase
label_desc: Use image node_id 2 for calling the TestLossLrMeterLoggingHook obj's underlying member method code with example usage: obj.test_logging(mock_get_rank) without return types