docstr: Test the subsample functionality.
code: def test_subsample(self, folder_dataset):
      """Test the subsample functionality."""
  
      sample_size = int(0.5 * len(folder_dataset))
      indices = random.sample(range(len(folder_dataset)), sample_size)
      subset = folder_dataset.subsample(indices)
  
      # check if the dataset has been subsampled to correct size
      assert len(subset) == sample_size
      # check if index has been reset
      assert subset.samples.index.start == 0
      assert subset.samples.index.stop == sample_size
  
file_path: anomalib/tests/pre_merge/datasets/test_dataset.py
imports: import random
  import pandas
  import pytest
  from anomalib.data import TaskType
  from anomalib.data.folder import FolderDataset
  from anomalib.data.utils import get_transforms, LabelName
  from anomalib.data.utils.split import concatenate_datasets, random_split
  from tests.helpers.dataset import get_dataset_path
label_desc: Use image node_id 1 for calling the TestAnomalibDataset obj's underlying member method code with example usage: obj.test_subsample(folder_dataset) without return types