code: def test_identity(tmpdir):
      class IdentityTransform(InputTransform):
          def per_sample_transform(self) -> Callable:
              return ApplyToKeys(
                  DataKeys.INPUT,
                  np.array,
              )
  
          def per_batch_transform(self) -> Callable:
              return lambda x: x
  
      tmp_dir = Path(tmpdir)
  
      # create random dummy data
  
      os.makedirs(str(tmp_dir / "images"))
      os.makedirs(str(tmp_dir / "targets"))
  
      images = [str(tmp_dir / "images" / "img1.png")]
  
      targets = [str(tmp_dir / "targets" / "img1.png")]
  
      num_classes: int = 2
      img_size: Tuple[int, int] = (128, 128)
      images_data, targets_data = create_random_data(
          images, targets, img_size, num_classes
      )
  
      # instantiate the data module
  
      dm = SemanticSegmentationData.from_files(
          test_files=images,
          test_targets=targets,
          batch_size=1,
          num_workers=0,
          num_classes=num_classes,
          transform=IdentityTransform(),
      )
  
      assert dm is not None
      assert dm.test_dataloader() is not None
  
      # check test data
      data = next(iter(dm.test_dataloader()))
      imgs, labels = data[DataKeys.INPUT], data[DataKeys.TARGET]
      assert imgs.shape == (1, 128, 128, 3)
      assert labels.shape == (1, 128, 128)
      assert torch.allclose(
          imgs, torch.from_numpy(np.array(images_data[0]))
      )
      assert torch.allclose(
          labels, torch.from_numpy(np.array(targets_data[0]))[:, :, 0]
      )
  
imports: import os
  from pathlib import Path
  from typing import Callable, Dict, List, Tuple
  import numpy
  import pytest
  import torch
  from flash import Trainer
  from flash.core.data.io.input import DataKeys
  from flash.core.data.io.input_transform import InputTransform
  from flash.core.data.transforms import ApplyToKeys
  from flash.core.utilities.imports import _FIFTYONE_AVAILABLE, _MATPLOTLIB_AVAILABLE, _PIL_AVAILABLE, _SEGMENTATION_MODELS_AVAILABLE, _TOPIC_IMAGE_AVAILABLE
  from flash.image import SemanticSegmentation, SemanticSegmentationData
label_desc: Use image node_id 2 for calling the TestSemanticSegmentationData obj's underlying member method code with example usage: obj.test_identity(tmpdir) and returns: ApplyToKeys, function