code: def test_data(self):
      assert self.m.data.dtype == self.dtype
      testing.assert_array_equal(
          self.m.data, cupy.array([[0, 1, 2], [3, 4, 5]], self.dtype)
      )
  
imports: import pickle
  import unittest
  import numpy
  import pytest
  import cupy
  from cupy import testing
  from cupy.cuda import driver
  from cupy.cuda import runtime
  from cupyx.scipy import sparse
label_desc: Use image node_id 3 for calling the TestDiaMatrix obj's underlying member method code with example usage: obj.test_data() without return types