code: def test_fetching_dataloader_iter_running_stages(fn, tmp_path):
      class TestModel(BoringModel):
          def fetch(self, data_fetcher, dataloader_iter):
              assert isinstance(
                  data_fetcher, _DataLoaderIterDataFetcher
              )
              batch, batch_idx, _ = next(dataloader_iter)
              assert data_fetcher.fetched == batch_idx + 1
              return batch
  
          def validation_step(self, dataloader_iter):
              data_fetcher = self.trainer.validate_loop._data_fetcher
              batch = self.fetch(data_fetcher, dataloader_iter)
              return super().validation_step(batch, 0)
  
          def test_step(self, dataloader_iter):
              data_fetcher = self.trainer.test_loop._data_fetcher
              batch = self.fetch(data_fetcher, dataloader_iter)
              return super().test_step(batch, 0)
  
          def predict_step(self, dataloader_iter):
              data_fetcher = self.trainer.predict_loop._data_fetcher
              batch = self.fetch(data_fetcher, dataloader_iter)
              return super().test_step(batch, 0)
  
      model = TestModel()
      trainer = Trainer(
          default_root_dir=tmp_path, fast_dev_run=1, accelerator="cpu"
      )
      trainer_fn = getattr(trainer, fn)
      trainer_fn(model)
  
imports: from collections import Counter
  from typing import Any, Iterator
  import pytest
  import torch
  from lightning.pytorch import LightningDataModule, Trainer
  from lightning.pytorch.demos.boring_classes import BoringModel, RandomDataset
  from lightning.pytorch.loops.fetchers import _DataLoaderIterDataFetcher, _PrefetchDataFetcher
  from lightning.pytorch.profilers import SimpleProfiler
  from lightning.pytorch.utilities.combined_loader import CombinedLoader
  from lightning.pytorch.utilities.exceptions import MisconfigurationException
  from lightning.pytorch.utilities.types import STEP_OUTPUT
  from torch import Tensor
  from torch.utils.data import DataLoader, Dataset, IterableDataset
  from tests_pytorch.helpers.runif import RunIf
label_desc: Use image node_id 6 for calling a global function with example usage: test_fetching_dataloader_iter_running_stages(fn, tmp_path) and returns: batch, super, super, super