code: def test_open_hdf5_s3(
      mock_fsspec,
  ):  # pylint: disable=redefined-outer-name
      """Test that open_hdf5_s3 calls fsspec.open() with the expected arguments."""
  
      ret = hdf5.open_hdf5_s3("/bucket")
  
      assert isinstance(ret, h5py.File)
      mock_fsspec.open.assert_called_once_with(
          "/bucket",
          **{"cache_type": "mmap", "block_size": 8 * (2**20)},
      )
  
file_path: pennylane/tests/data/base/test_hdf5.py
imports: from unittest.mock import MagicMock
  import pytest
  from pennylane.data.base import hdf5
label_desc: Use image node_id 3 for calling a global function with example usage: test_open_hdf5_s3(mock_fsspec) without return types