code: def test_numpy_serializer_from_buffer_or_file(numpy_serializer):
      array = np.ones((2, 3))
      stream = io.BytesIO()
      np.save(stream, array)
      stream.seek(0)
  
      result = numpy_serializer.serialize(stream)
  
      assert np.array_equal(array, np.load(io.BytesIO(result)))
  
imports: from __future__ import absolute_import
  import io
  import json
  import os
  import numpy
  import pytest
  import scipy.sparse
  from sagemaker.serializers import CSVSerializer, NumpySerializer, JSONSerializer, IdentitySerializer, SparseMatrixSerializer, JSONLinesSerializer, LibSVMSerializer, DataSerializer
  from tests.unit import DATA_DIR
label_desc: Use image node_id 18 for calling a global function with example usage: test_numpy_serializer_from_buffer_or_file(numpy_serializer) without return types