test: verify portfolio loss against finalized engine accounting

crates/fidc-core/src/platform_expr_strategy.rs

@@ -1468,6 +1468,7 @@ impl PlatformExprStrategy {
         }
         self.portfolio_loss_state = Some(state);
         Ok(())
+    }
 
     fn market_cap_storage_to_strategy_unit(value: f64) -> f64 {
         value
@@ -14639,6 +14640,81 @@ mod tests {
         .expect("single-symbol platform dataset")
     }
 
+    #[test]
+    fn portfolio_loss_observes_finalized_nav_after_fees_and_cash_flows() {
+        use std::sync::Mutex;
+        use crate::{BacktestConfig, BacktestEngine, BrokerSimulator, ChinaEquityRuleHooks};
+
+        struct Capture {
+            inner: PlatformExprStrategy,
+            first: NaiveDate,
+            rows: Arc<Mutex<Vec<(ClosedPortfolioSession, crate::portfolio_loss::PortfolioLossDecision)>>>,
+        }
+        impl Strategy for Capture {
+            fn name(&self) -> &str { "portfolio-loss-lifecycle-test" }
+            fn requires_minute_callbacks(&self) -> bool { false }
+            fn before_trading(&mut self, ctx: &StrategyContext<'_>) -> Result<(), BacktestError> {
+                self.inner.before_trading(ctx)
+            }
+            fn on_day(&mut self, ctx: &StrategyContext<'_>) -> Result<StrategyDecision, BacktestError> {
+                let mut decision = self.inner.on_day(ctx)?;
+                if ctx.execution_date == self.first {
+                    decision.order_intents.push(OrderIntent::SetManagementFeeRate { rate: 0.001, reason: "fee accounting test".to_owned() });
+                }
+                if ctx.execution_date == self.first + Duration::days(5) {
+                    decision.order_intents.push(OrderIntent::DepositWithdraw { amount: 10_000.0, receiving_days: 0, reason: "unit NAV flow test".to_owned() });
+                }
+                Ok(decision)
+            }
+            fn on_process_event(&mut self, ctx: &StrategyContext<'_>, event: &ProcessEvent) -> Result<(), BacktestError> {
+                self.inner.on_process_event(ctx, event)?;
+                if event.kind == ProcessEventKind::PostSettlement {
+                    let state = self.inner.portfolio_loss_state().unwrap();
+                    self.rows.lock().unwrap().push((state.last_session().unwrap().clone(), state.last_decision().unwrap().clone()));
+                }
+                Ok(())
+            }
+        }
+        let first = d(2023, 1, 3);
+        let dates = (0..25).map(|day| first + Duration::days(day)).collect::<Vec<_>>();
+        let mut parts = single_symbol_platform_data(&dates, "000001.SZ").snapshot_components();
+        for (index, row) in parts.market.iter_mut().enumerate() {
+            let price = (1000.0 * 0.99_f64.powi(index as i32)).round() / 100.0;
+            row.day_open = price; row.open = price; row.high = price; row.low = price;
+            row.close = price; row.last_price = price; row.bid1 = price; row.ask1 = price;
+            row.prev_close = price / 0.99; row.upper_limit = price * 1.1; row.lower_limit = price * 0.9;
+        }
+        let data = DataSet::from_components(parts.instruments, parts.market, parts.factors, parts.candidates, parts.benchmarks).unwrap();
+        let mut config = PlatformExprStrategyConfig::generic();
+        config.universe_include = Some(BTreeSet::from(["000001.SZ".to_owned()]));
+        config.stock_filter_expr = "true".to_owned(); config.rank_expr = "1.0".to_owned();
+        config.selection_limit_expr = "1".to_owned(); config.max_positions = 1;
+        config.market_cap_lower_expr = "0.0".to_owned(); config.market_cap_upper_expr = "1000.0".to_owned();
+        config.exposure_expr = "0.9".to_owned(); config.refresh_rate = 1; config.refresh_rate_expr = "1".to_owned();
+        config.portfolio_loss_control = Some(PortfolioLossConfig { lookback: 10, loss_trigger: 0.05, floor_exposure: 0.2, cooldown_trading_days: 3 });
+        let rows = Arc::new(Mutex::new(Vec::new()));
+        let strategy = Capture { inner: PlatformExprStrategy::new(config), first, rows: Arc::clone(&rows) };
+        let broker = BrokerSimulator::new(ChinaAShareCostModel::default(), ChinaEquityRuleHooks)
+            .with_matching_type(MatchingType::CurrentBarClose);
+        let mut engine = BacktestEngine::new(data, strategy, broker, BacktestConfig {
+            initial_cash: 10_000.0, benchmark_code: "000852.SH".to_owned(), start_date: Some(first),
+            end_date: dates.last().copied(), decision_lag_trading_days: 0, execution_price_field: PriceField::Close,
+        });
+        let result = engine.run().unwrap();
+        let records = rows.lock().unwrap();
+        assert_eq!(records.len(), dates.len());
+        assert!(result.fills.len() > 1);
+        assert_eq!(result.equity_curve[5].external_cash_flow, 10_000.0);
+        assert!(records.iter().any(|(_, decision)| decision.newly_triggered));
+        for ((session, decision), equity) in records.iter().zip(&result.equity_curve) {
+            assert_eq!(session.date, equity.date);
+            assert_eq!(session.end_unit_nav.to_bits(), equity.unit_nav.to_bits());
+            assert!(decision.observed_through.is_none_or(|date| date < session.date));
+            if decision.observation_count < 10 { assert!(!decision.threshold_breached); }
+        }
+        assert!(result.equity_curve[5].unit_nav < result.equity_curve[4].unit_nav);
+    }
+
     #[test]
     fn stock_state_cache_resets_before_reusing_compact_keys_on_another_date() {
         let dates = [d(2025, 1, 2), d(2025, 1, 3)];