test: test Lifetime class

app/models/Lifetime.test.ts

@@ -0,0 +1,67 @@
+import { Lifetime } from "./Lifetime";
+import { createTestProperty, createTestLifetime } from "./testHelpers";
+
+let lifetime = createTestLifetime();
+
+beforeEach(() => {
+    lifetime = createTestLifetime();
+})
+
+it("can be instantiated", () => {
+    expect(lifetime).toBeInstanceOf(Lifetime);
+})
+
+it("creates an array with the correct number of years", () => {
+    expect(lifetime.lifetimeData).toHaveLength(40)
+})
+
+it("reduces mortgage payments to 0 after the mortgage term is reached", () => {
+    expect(lifetime.lifetimeData[35].newbuildHouseMortgageYearly).toBe(0);
+    expect(lifetime.lifetimeData[34].marketLandMortgageYearly).toBe(0);
+    expect(lifetime.lifetimeData[33].fairholdLandMortgageYearly).toBe(0);
+    expect(lifetime.lifetimeData[32].marketLandMortgageYearly).toBe(0);
+})
+
+describe("resale values", () => {
+    it("correctly calculates for a newbuild house", () => {
+        // Test newbuild (age 0)
+        lifetime = createTestLifetime({
+            property: createTestProperty({ age: 0 })
+        });
+        expect(lifetime.lifetimeData[0].depreciatedHouseResaleValue).toBe(186560);
+    });
+    it("correctly calculates for a 10-year old house", () => {    // Test 10-year-old house
+        lifetime = createTestLifetime({
+            property: createTestProperty({ 
+                age: 10,
+                newBuildPricePerMetre: 2120,
+                size: 88 
+            })
+        }); 
+        // Calculate expected depreciation running `calculateDepreciatedBuildPrice()` method on its own
+        const houseY10 = createTestProperty({ 
+            age: 10,
+            newBuildPricePerMetre: 2120,
+            size: 88 
+        })           
+        const depreciatedHouseY10 = houseY10.calculateDepreciatedBuildPrice()
+        expect(lifetime.lifetimeData[0].depreciatedHouseResaleValue).toBe(depreciatedHouseY10);
+    });
+    it("depreciates the house over time", () => {
+        // Test value changes over time
+        expect(lifetime.lifetimeData[0].depreciatedHouseResaleValue).toBeGreaterThan(
+            lifetime.lifetimeData[10].depreciatedHouseResaleValue);
+    })
+});
+
+
+it("correctly ages the house", () => {
+    lifetime = createTestLifetime({
+        property: createTestProperty({ age: 10 }) 
+    })
+
+    expect(lifetime.lifetimeData[0].houseAge).toBe(10);
+    expect(lifetime.lifetimeData[5].houseAge).toBe(15);
+    expect(lifetime.lifetimeData[20].houseAge).toBe(30);
+    expect(lifetime.lifetimeData[39].houseAge).toBe(49);
+})