TF_Operation* add2 = Add(add1, feed3, func_graph_, s_, "add2");
  Define(-1, {}, {feed1, feed2, feed3}, {add1, add2}, {"my_out", "my_out"},
         true);
  EXPECT_EQ(TF_INVALID_ARGUMENT, TF_GetCode(s_));
  EXPECT_EQ(string("Cannot have duplicate output names. Name 'my_out' "
                   "appears more than once in 'output_names' array."),
            string(TF_Message(s_)));
}