code: def test_eye(self, xp, sp):
      x = sp.identity(3, dtype=self.dtype, format=self.format)
      assert isinstance(x, sp.spmatrix)
      assert x.format == self.format
      return x
  
imports: import functools
  import re
  from unittest import mock
  import numpy
  import pytest
  import cupy
  from cupy import testing
  from cupy.cuda import runtime
  from cupyx.scipy import sparse
  from cupyx.scipy.sparse import _construct
label_desc: Use image node_id 1 for calling the TestIdentity obj's underlying member method code with example usage: obj.test_eye(xp, sp) and returns: x