code: def test_buffer_size(self):
      data = np.zeros(10)
      B = Buffer(data=data)
      assert B.nbytes == data.nbytes
  
imports: import unittest
  import numpy
  from vispy.testing import run_tests_if_main
  from vispy.gloo.buffer import Buffer, DataBuffer, DataBufferView, VertexBuffer, IndexBuffer
label_desc: Use image node_id 7 for calling the BufferTest obj's underlying member method code with example usage: obj.test_buffer_size() without return types