code: def test_tri(self, xp, dtype):
      return xp.tri(*self.shape, k=0, dtype=dtype)
  
imports: import unittest
  import numpy
  import pytest
  import cupy
  from cupy import testing
label_desc: Use image node_id 1 for calling the TestTri obj's underlying member method code with example usage: obj.test_tri(xp, dtype) and returns: xp