LibJS: Implement Temporal.Instant.prototype.toZonedDateTime()

Userland/Libraries/LibJS/Tests/builtins/Temporal/Instant/Instant.prototype.toZonedDateTime.js

@@ -0,0 +1,54 @@
+describe("correct behavior", () => {
+    test("length is 1", () => {
+        expect(Temporal.Instant.prototype.toZonedDateTime).toHaveLength(1);
+    });
+
+    test("basic functionality", () => {
+        const instant = new Temporal.Instant(1625614921123456789n);
+        const calendar = new Temporal.Calendar("iso8601");
+        const timeZone = new Temporal.TimeZone("UTC");
+        const zonedDateTime = instant.toZonedDateTime({ calendar, timeZone });
+        expect(zonedDateTime.year).toBe(2021);
+        expect(zonedDateTime.month).toBe(7);
+        expect(zonedDateTime.day).toBe(6);
+        expect(zonedDateTime.hour).toBe(23);
+        expect(zonedDateTime.minute).toBe(42);
+        expect(zonedDateTime.second).toBe(1);
+        expect(zonedDateTime.millisecond).toBe(123);
+        expect(zonedDateTime.microsecond).toBe(456);
+        expect(zonedDateTime.nanosecond).toBe(789);
+        expect(zonedDateTime.calendar).toBe(calendar);
+        expect(zonedDateTime.timeZone).toBe(timeZone);
+    });
+});
+
+describe("errors", () => {
+    test("this value must be a Temporal.Instant object", () => {
+        expect(() => {
+            Temporal.Instant.prototype.toZonedDateTime.call("foo");
+        }).toThrowWithMessage(TypeError, "Not a Temporal.Instant");
+    });
+
+    test("items argument must be an object", () => {
+        const instant = new Temporal.Instant(0n);
+        for (const value of [123, NaN, Infinity, true, false, null, undefined]) {
+            expect(() => {
+                instant.toZonedDateTime(value);
+            }).toThrowWithMessage(TypeError, `${value} is not an object`);
+        }
+    });
+
+    test("items argument must have a 'calendar' property", () => {
+        const instant = new Temporal.Instant(0n);
+        expect(() => {
+            instant.toZonedDateTime({});
+        }).toThrowWithMessage(TypeError, "Required property calendar is missing or undefined");
+    });
+
+    test("items argument must have a 'timeZone' property", () => {
+        const instant = new Temporal.Instant(0n);
+        expect(() => {
+            instant.toZonedDateTime({ calendar: {} });
+        }).toThrowWithMessage(TypeError, "Required property timeZone is missing or undefined");
+    });
+});