code: def test_diag_scaler(self):
      for xp in (numpy, cupy):
          with pytest.raises(ValueError):
              xp.diag(1)
  
imports: import unittest
  import numpy
  import pytest
  import cupy
  from cupy import testing
label_desc: Use image node_id 9 for calling the TestMatrix obj's underlying member method code with example usage: obj.test_diag_scaler() without return types