switchyard_libsy/algorithms/
noop.rs

1// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
2// SPDX-License-Identifier: Apache-2.0
3
4//! Test-only algorithm that returns a hard-coded response without calling a backend.
5
6use std::sync::Arc;
7
8use switchyard_protocol::{
9    AggLlmResponse, ContentBlock, LlmResponse, Request, Response, ResponseOutput, Role, StopReason,
10};
11
12use crate::Result;
13use crate::core::algorithm::{Algorithm, Driver};
14use switchyard_protocol::Decision;
15
16/// Test helper that returns a hard-coded response without routing or model I/O.
17pub struct Noop {}
18
19#[async_trait::async_trait]
20impl Algorithm for Noop {
21    fn name(&self) -> &str {
22        "noop"
23    }
24
25    async fn route(self: Arc<Self>, driver: Driver, request: Request) -> Result<Response> {
26        let model = request
27            .requested_model()
28            .unwrap_or("switchyard/noop")
29            .to_string();
30        let decision: Decision = Decision::new(
31            model.clone(),
32            Some("noop returned its synthetic response".to_string()),
33            true,
34        );
35        driver.decide(decision.clone()).await?;
36
37        let llm_response = LlmResponse::Agg(AggLlmResponse {
38            id: Some("switchyard-noop".to_string()),
39            model: Some(model),
40            outputs: vec![ResponseOutput {
41                role: Role::Assistant,
42                content: vec![ContentBlock::Text {
43                    text: "OK".to_string(),
44                }],
45                stop_reason: Some(StopReason::EndTurn),
46            }],
47            ..Default::default()
48        });
49        let response = Response {
50            llm_response,
51            metadata: request.metadata.clone(),
52        };
53        Ok(response)
54    }
55}
56
57#[cfg(test)]
58mod tests {
59    use switchyard_protocol::{LlmRequest, Message, Role};
60
61    use super::*;
62    use crate::core::testing::{echo, test_drive};
63
64    #[tokio::test]
65    async fn test_noop_algo() -> Result<()> {
66        const TEST_MODEL: &str = "test_noop_algo";
67        let request = Request {
68            llm_request: LlmRequest {
69                model: Some(TEST_MODEL.to_string()),
70                messages: vec![Message::text(Role::User, "hi")],
71                ..LlmRequest::default()
72            },
73            raw_request: None,
74            metadata: None,
75        };
76
77        // `Noop` synthesizes its own response and never offloads a call, so `echo` is
78        // never reached.
79        let a: Arc<dyn Algorithm> = Arc::new(Noop {});
80        let (decisions, response) = test_drive(a, request, echo()).await?;
81        let Some(decision) = decisions.first() else {
82            panic!("Expected exactly one Decision");
83        };
84        assert_eq!(decision.selected_model_id(), TEST_MODEL);
85        assert!(decision.is_answer_call());
86        assert_eq!(response.selected_model(), Some(TEST_MODEL));
87        Ok(())
88    }
89}
switchyard_libsy/algorithms/noop.rs

switchyard_libsy/algorithms/
noop.rs
