code: def test_union1d(self, xp, dtype):
      x = xp.array([4, 1, 1, 1, 9, 9, 9], dtype=dtype)
      y = xp.array([4, 0, 5, 2, 0, 0, 5], dtype=dtype)
      return xp.union1d(x, y)
  
imports: import warnings
  import numpy
  from cupy import testing
label_desc: Use image node_id 1 for calling the TestUnion1d obj's underlying member method code with example usage: obj.test_union1d(xp, dtype) and returns: xp