LibJS: Implement Temporal.Duration.prototype.add

Userland/Libraries/LibJS/Tests/builtins/Temporal/Duration/Duration.prototype.add.js

@@ -0,0 +1,86 @@
+describe("correct behavior", () => {
+    test("length is 1", () => {
+        expect(Temporal.Duration.prototype.add).toHaveLength(1);
+    });
+
+    function checkCommonResults(durationResult) {
+        expect(durationResult.years).toBe(0);
+        expect(durationResult.months).toBe(0);
+        expect(durationResult.weeks).toBe(0);
+        expect(durationResult.days).toBe(3);
+        expect(durationResult.hours).toBe(3);
+        expect(durationResult.minutes).toBe(3);
+        expect(durationResult.seconds).toBe(3);
+        expect(durationResult.milliseconds).toBe(3);
+        expect(durationResult.microseconds).toBe(3);
+        expect(durationResult.nanoseconds).toBe(3);
+    }
+
+    test("basic functionality", () => {
+        const duration = new Temporal.Duration(0, 0, 0, 2, 2, 2, 2, 2, 2, 2);
+        const oneDuration = new Temporal.Duration(0, 0, 0, 1, 1, 1, 1, 1, 1, 1);
+        const durationResult = duration.add(oneDuration);
+
+        checkCommonResults(durationResult);
+    });
+
+    test("from duration-like", () => {
+        const duration = new Temporal.Duration(0, 0, 0, 2, 2, 2, 2, 2, 2, 2);
+        const oneDuration = {
+            days: 1,
+            hours: 1,
+            minutes: 1,
+            seconds: 1,
+            milliseconds: 1,
+            microseconds: 1,
+            nanoseconds: 1,
+        };
+        const durationResult = duration.add(oneDuration);
+
+        checkCommonResults(durationResult);
+    });
+
+    test("from string", () => {
+        const duration = new Temporal.Duration(0, 0, 0, 2, 2, 2, 2, 2, 2, 2);
+        const oneDuration = "P1DT1H1M1.001001001S";
+        const durationResult = duration.add(oneDuration);
+
+        checkCommonResults(durationResult);
+    });
+});
+
+describe("errors", () => {
+    test("this value must be a Temporal.Duration object", () => {
+        expect(() => {
+            Temporal.Duration.prototype.add.call("foo");
+        }).toThrowWithMessage(TypeError, "Not an object of type Temporal.Duration");
+    });
+
+    test("relativeTo is required when duration has calendar units", () => {
+        const yearDuration = new Temporal.Duration(1);
+        const monthDuration = new Temporal.Duration(0, 1);
+        const weekDuration = new Temporal.Duration(0, 0, 1);
+        const durationToAdd = { seconds: 1 };
+
+        expect(() => {
+            yearDuration.add(durationToAdd);
+        }).toThrowWithMessage(
+            RangeError,
+            "A starting point is required for balancing year, month or week"
+        );
+
+        expect(() => {
+            monthDuration.add(durationToAdd);
+        }).toThrowWithMessage(
+            RangeError,
+            "A starting point is required for balancing year, month or week"
+        );
+
+        expect(() => {
+            weekDuration.add(durationToAdd);
+        }).toThrowWithMessage(
+            RangeError,
+            "A starting point is required for balancing year, month or week"
+        );
+    });
+});