Meet SPIRITT, your company's autonomous workforce

@@ -38,9 +38,12 @@ impl Invoice3838     /// Total due, rounded once at the end.3939     pub fn total(&self) -> Money {40-        let mut sum = 0.0;41-        for line in &self.lines { sum += line.amount() }42-        Money::from_f64(sum * (1.0 + self.tax))40+        let net: Money = self.lines.iter().map(Line::amount).sum();41+        let tax = self.tax.apply(net);42+        (net + tax).round_half_even()4343     }

SPIRITT Floats drifted by a cent on large invoices. Now it sums in exact Money and rounds once, like invoice.ts. 214 tests and 72 hours of shadow traffic match to the cent.

4444 45+    #[test]46+    fn matches_legacy_rounding() { assert_eq!(fixture().total(), cents(1999)) }47+4548     pub fn due_date(&self) -> Date {

@@ -88,6 +91,14 @@ impl Invoice8891     pub fn apply_credit(&mut self, credit: Money) {89-        self.balance = self.balance - credit;92+        self.balance = self.balance.saturating_sub(credit);93+        self.events.push(Event::CreditApplied(credit));9094     }9195 96+    pub fn is_paid(&self) -> bool {97+        self.balance.is_zero()98+    }99+100+    #[test]101+    fn credit_never_goes_negative() { … }92102 }

SPIRITT Credits can no longer push a balance below zero, matching the Node behavior customers rely on.