code: def test_dataloader(self):
      test_data = np.random.randint(0, 256, size=[3, 4, 5])
      datalist_dict, datalist_array = [], []
      with tempfile.TemporaryDirectory() as tempdir:
          for i in range(4):
              filepath = os.path.join(tempdir, f"test_data{i}.npz")
              np.savez(filepath, test_data)
              datalist_dict.append({"image": filepath})
              datalist_array.append(filepath)
  
          num_workers = 2 if sys.platform == "linux" else 0
          loader = DataLoader(
              Dataset(
                  data=datalist_dict,
                  transform=LoadImaged(
                      keys="image", reader=NumpyReader()
                  ),
              ),
              batch_size=2,
              num_workers=num_workers,
          )
          for d in loader:
              for c in d["image"]:
                  assert_allclose(c, test_data, type_test=False)
  
          loader = DataLoader(
              Dataset(
                  data=datalist_array,
                  transform=LoadImage(reader=NumpyReader()),
              ),
              batch_size=2,
              num_workers=num_workers,
          )
          for d in loader:
              for c in d:
                  assert_allclose(c, test_data, type_test=False)
  
file_path: MONAI/tests/test_numpy_reader.py
imports: from __future__ import annotations
  import os
  import sys
  import tempfile
  import unittest
  import numpy
  from monai.data import DataLoader, Dataset, NumpyReader
  from monai.transforms import LoadImage, LoadImaged
  from tests.utils import assert_allclose
label_desc: Use image node_id 7 for calling the TestNumpyReader obj's underlying member method code with example usage: obj.test_dataloader() without return types