diff --git a/crates/fidc-core/src/engine.rs b/crates/fidc-core/src/engine.rs
index 0a17167..97410bd 100644
--- a/crates/fidc-core/src/engine.rs
+++ b/crates/fidc-core/src/engine.rs
@@ -4211,6 +4211,34 @@ mod tests {
         }
     }
 
+    #[derive(Debug)]
+    struct AuctionBuyWhenDecisionDateStrategy {
+        decision_date: NaiveDate,
+    }
+
+    impl Strategy for AuctionBuyWhenDecisionDateStrategy {
+        fn name(&self) -> &str {
+            "auction_buy_when_decision_date"
+        }
+
+        fn open_auction(
+            &mut self,
+            ctx: &StrategyContext<'_>,
+        ) -> Result<StrategyDecision, super::BacktestError> {
+            if ctx.decision_date == self.decision_date && ctx.portfolio.position(SYMBOL).is_none() {
+                return Ok(StrategyDecision {
+                    order_intents: vec![OrderIntent::Shares {
+                        symbol: SYMBOL.to_string(),
+                        quantity: 100,
+                        reason: "auction_test_buy".to_string(),
+                    }],
+                    ..StrategyDecision::default()
+                });
+            }
+            Ok(StrategyDecision::default())
+        }
+    }
+
     #[derive(Debug)]
     struct ScheduledBuyStrategy {
         rule: ScheduleRule,
@@ -4915,7 +4943,7 @@ mod tests {
 
         let result = BacktestEngine::new(
             dataset,
-            BuyWhenDecisionDateStrategy {
+            AuctionBuyWhenDecisionDateStrategy {
                 decision_date: second,
             },
             broker,