found_scalar_const = true;
    } else if (IsAddN(n, 2)) {
      EXPECT_FALSE(found_add);
      found_add = true;
    } else {
      ADD_FAILURE() << "Unexpected NodeDef: " << n.DebugString();
    }
  }
  EXPECT_TRUE(found_placeholder);
  EXPECT_TRUE(found_scalar_const);
  EXPECT_TRUE(found_add);

  // Add another oper to the graph.
  TF_Operation* neg = Neg(add, graph, s);