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, ModelId, Request, Response, ResponseOutput, Role,
10    StopReason,
11};
12
13use crate::core::algorithm::{Algorithm, Driver};
14use crate::{Result, RoutingOutcome};
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<RoutingOutcome> {
26        let model_id = request
27            .model_id()
28            .unwrap_or_else(|| ModelId::from("switchyard/noop"));
29        tracing::info!(target = %model_id, "noop returned its synthetic response");
30        let llm_response = LlmResponse::Agg(AggLlmResponse {
31            id: Some("switchyard-noop".to_string()),
32            model: Some(model_id.to_string()),
33            outputs: vec![ResponseOutput {
34                role: Role::Assistant,
35                content: vec![ContentBlock::Text {
36                    text: "OK".to_string(),
37                }],
38                stop_reason: Some(StopReason::EndTurn),
39            }],
40            ..Default::default()
41        });
42        let response = Response {
43            llm_response,
44            metadata: request.metadata.clone(),
45        };
46        Ok(RoutingOutcome::answered(model_id, request, response))
47    }
48}
49
50#[cfg(test)]
51mod tests {
52    use switchyard_protocol::{LlmRequest, Message, Role};
53
54    use super::*;
55    use crate::core::testing::{echo, test_drive};
56
57    #[tokio::test]
58    async fn test_noop_algo() -> Result<()> {
59        const TEST_MODEL: &str = "test_noop_algo";
60        let request = Request {
61            llm_request: LlmRequest {
62                model: Some(TEST_MODEL.to_string()),
63                messages: vec![Message::text(Role::User, "hi")],
64                ..LlmRequest::default()
65            },
66            raw_request: None,
67            metadata: None,
68        };
69
70        // `Noop` synthesizes its own response and never offloads a call, so `echo` is
71        // never reached.
72        let a: Arc<dyn Algorithm> = Arc::new(Noop {});
73        let (selected_model, response) = test_drive(a, request, echo()).await?;
74        assert_eq!(selected_model, TEST_MODEL);
75        assert_eq!(response.selected_model(), Some(TEST_MODEL));
76        Ok(())
77    }
78}
switchyard_libsy/algorithms/noop.rs

switchyard_libsy/algorithms/
noop.rs
