std::set<string> factories_sorted;
  for (const auto& factory : GetFactories())
    factories_sorted.insert(factory.first);
  const char* comma = "";
  for (const string& factory : factories_sorted) {
    msg += comma + factory;
    comma = ", ";
  }
  msg += ")";

  return errors::InvalidArgument(msg.c_str());
}

static TracingContext* CreateTracingExecutionContext(const char* fn_name,

  TFE_Op* non_comm_op = TFE_NewOp(ctx, "TestNonCommUnavailable", status);
  CHECK_EQ(TF_OK, TF_GetCode(status)) << TF_Message(status);
  TFE_TensorHandle* retval[1] = {};
  int num_retvals = 1;
  TFE_Execute(non_comm_op, retval, &num_retvals, status);
  EXPECT_EQ(TF_INTERNAL, TF_GetCode(status)) << TF_Message(status);
  TFE_DeleteOp(non_comm_op);