From b8797a9208cf371579689bf8d558cf8217981e4a Mon Sep 17 00:00:00 2001
From: Antonio Ventilii <antonio.ventilii@dfinity.org>
Date: Wed, 9 Sep 2026 11:24:37 +0200
Subject: [PATCH] chore(backend): return a ready future from the composite
 exchange test mock

Rust 1.98 adds clippy::unused_async_trait_impl, which fires on an async trait impl with no .await in its body. With -D warnings this fails the backend lint job.
---
 src/backend/src/exchange/composite.rs | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/backend/src/exchange/composite.rs b/src/backend/src/exchange/composite.rs
index 95c6a668278..6ff37bf1bb6 100644
--- a/src/backend/src/exchange/composite.rs
+++ b/src/backend/src/exchange/composite.rs
@@ -88,7 +88,11 @@ pub(crate) async fn fetch_all_prices<P: ExchangePriceProvider>(
 
 #[cfg(test)]
 mod tests {
-    use std::{cell::RefCell, rc::Rc};
+    use std::{
+        cell::RefCell,
+        future::{ready, Future},
+        rc::Rc,
+    };
 
     use candid::Principal;
     use futures::executor::block_on;
@@ -106,11 +110,11 @@ mod tests {
     }
 
     impl ExchangePriceProvider for MockPrimaryProvider {
-        async fn fetch_prices(
+        fn fetch_prices(
             &self,
             _token_ids: &[StoredTokenId],
-        ) -> Result<Vec<(StoredTokenId, ExchangeData)>, String> {
-            self.result.clone()
+        ) -> impl Future<Output = Result<Vec<(StoredTokenId, ExchangeData)>, String>> {
+            ready(self.result.clone())
         }
     }