code: def ternary_op_given_shape_test_data(self):
      smoke_data = [
          # TODO: add test in BackendsTestData
          dict(
              func_name="mat_from_diag_triu_tril",
              shape_a=(2,),
              shape_b=(1,),
              shape_c=(1,),
          ),
      ]
      return self.generate_tests(smoke_data)
  
imports: import numpy
  import geomstats.backend
  from geomstats.geometry.matrices import Matrices
  from geomstats.geometry.spd_matrices import SPDMatrices
  from geomstats.geometry.symmetric_matrices import SymmetricMatrices
  from geomstats.test.data import TestData
label_desc: Use image node_id 15 for calling the DtypeTestData obj's underlying member method code with example usage: obj.ternary_op_given_shape_test_data() and returns: self