code: def test_getitem_index(self):
      dtype = np.dtype(
          [
              ("position", np.float32, 3),
              ("texcoord", np.float32, 2),
              ("color", np.float32, 4),
          ]
      )
      data = np.zeros(10, dtype=dtype)
      B = DataBuffer(data)
      Z = B[0:1]
      assert Z.base == B
      assert Z.id == B.id
      assert Z.nbytes == 1 * (3 + 2 + 4) * np.dtype(np.float32).itemsize
      assert Z.offset == 0
      assert Z.size == 1
      assert Z.itemsize == (3 + 2 + 4) * np.dtype(np.float32).itemsize
      assert Z.stride == (3 + 2 + 4) * np.dtype(np.float32).itemsize
      assert Z.dtype == B.dtype
      assert "DataBufferView" in repr(Z)
  
      # There's a few things we cannot do with a view
      self.assertRaises(RuntimeError, Z.set_data, data)
      self.assertRaises(RuntimeError, Z.set_subdata, data)
      self.assertRaises(RuntimeError, Z.resize_bytes, 20)
      self.assertRaises(RuntimeError, Z.__getitem__, 3)
      self.assertRaises(RuntimeError, Z.__setitem__, 3, data)
  
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 6 for calling the DataBufferTest obj's underlying member method code with example usage: obj.test_getitem_index() without return types