diff --git a/crates/fidc-core/src/platform_expr_strategy.rs b/crates/fidc-core/src/platform_expr_strategy.rs
index 754a84e..73ad31a 100644
--- a/crates/fidc-core/src/platform_expr_strategy.rs
+++ b/crates/fidc-core/src/platform_expr_strategy.rs
@@ -23976,7 +23976,7 @@ mod tests {
                     turnover_ratio: Some(1.0),
                     effective_turnover_ratio: Some(1.0),
                     adjustment_factor_backward1: None,
-                    extra_factors: BTreeMap::new(),
+                    extra_factors: BTreeMap::from([("amount".into(), 20_000_000.0)]),
                 },
                 DailyFactorSnapshot {
                     date: factor_date,
@@ -23987,7 +23987,7 @@ mod tests {
                     turnover_ratio: Some(1.0),
                     effective_turnover_ratio: Some(1.0),
                     adjustment_factor_backward1: None,
-                    extra_factors: BTreeMap::new(),
+                    extra_factors: BTreeMap::from([("amount".into(), 10_000_000.0)]),
                 },
                 DailyFactorSnapshot {
                     date: decision_date,
@@ -24138,6 +24138,10 @@ mod tests {
             .stock_state_with_factor_date(&ctx, decision_date, decision_date, limit_symbol)
             .expect("next-open decision state");
         assert_eq!(decision_day_state.amount, 30_000_000.0);
+        let prior_factor_state = strategy
+            .stock_state_with_factor_date(&ctx, decision_date, factor_date, limit_symbol)
+            .expect("previous factor-day state");
+        assert_eq!(prior_factor_state.amount, 20_000_000.0);
 
         let decision = strategy.on_day(&ctx).expect("platform decision");