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tests/unit/calculations.test.ts

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+import { describe, expect, it } from "vitest";
+
+import { calculateAddonTotalCents, calculateExpectedCash, calculateLoyaltyDiscountCents, calculateUtilizationPct } from "@/server/services/calculations";
+
+describe("calculateExpectedCash", () => {
+  it("computes shift expected cash with deposits and withdrawals", () => {
+    const value = calculateExpectedCash({
+      startingCashCents: 10_000,
+      cashSalesCents: 24_500,
+      depositsCents: 2_000,
+      withdrawalsCents: 1_500
+    });
+    expect(value).toBe(35_000);
+  });
+});
+
+describe("calculateUtilizationPct", () => {
+  it("returns rounded percentage", () => {
+    expect(calculateUtilizationPct(43, 120)).toBe(35.83);
+  });
+
+  it("guards zero window", () => {
+    expect(calculateUtilizationPct(10, 0)).toBe(0);
+  });
+});
+
+describe("calculateLoyaltyDiscountCents", () => {
+  it("computes rounded discount by percentage", () => {
+    expect(calculateLoyaltyDiscountCents(4_500, 50)).toBe(2_250);
+  });
+
+  it("caps percentage and guards invalid values", () => {
+    expect(calculateLoyaltyDiscountCents(3_000, 150)).toBe(3_000);
+    expect(calculateLoyaltyDiscountCents(3_000, -20)).toBe(0);
+  });
+});
+
+describe("calculateAddonTotalCents", () => {
+  it("sums addon quantities by configured prices", () => {
+    expect(
+      calculateAddonTotalCents({
+        detergentQty: 2,
+        softenerQty: 1,
+        bleachQty: 3,
+        detergentAddonCents: 500,
+        softenerAddonCents: 500,
+        bleachAddonCents: 500
+      })
+    ).toBe(3_000);
+  });
+});