LibJS: Implement Temporal.Duration.prototype.with()

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

@@ -0,0 +1,87 @@
+const DURATION_PROPERTIES = [
+    "years",
+    "months",
+    "weeks",
+    "days",
+    "hours",
+    "minutes",
+    "seconds",
+    "milliseconds",
+    "microseconds",
+    "nanoseconds",
+];
+
+describe("correct behavior", () => {
+    test("length is 1", () => {
+        expect(Temporal.Duration.prototype.with).toHaveLength(1);
+    });
+
+    test("basic functionality", () => {
+        const duration = new Temporal.Duration(1, 2, 3).with({ years: 4, foo: 5, weeks: 6 });
+        expect(duration.years).toBe(4);
+        expect(duration.months).toBe(2);
+        expect(duration.weeks).toBe(6);
+    });
+
+    test("each property is looked up from the object", () => {
+        for (const property of DURATION_PROPERTIES) {
+            const duration = new Temporal.Duration().with({ [property]: 1 });
+            expect(duration[property]).toBe(1);
+        }
+    });
+
+    test("each property is coerced to number", () => {
+        for (const property of DURATION_PROPERTIES) {
+            const duration = new Temporal.Duration().with({ [property]: "1" });
+            expect(duration[property]).toBe(1);
+        }
+    });
+});
+
+test("errors", () => {
+    test("this value must be a Temporal.Duration object", () => {
+        expect(() => {
+            Temporal.Duration.prototype.with.call("foo");
+        }).toThrowWithMessage(TypeError, "Not a Temporal.Duration");
+    });
+
+    test("argument is not an object", () => {
+        expect(() => {
+            new Temporal.Duration().with("foo");
+        }).toThrowWithMessage(TypeError, "foo is not an object");
+        expect(() => {
+            new Temporal.Duration().with(42);
+        }).toThrowWithMessage(TypeError, "42 is not an object");
+    });
+
+    test("argument is an invalid duration-like object", () => {
+        expect(() => {
+            new Temporal.Duration().with({});
+        }).toThrowWithMessage(TypeError, "Invalid duration-like object");
+        expect(() => {
+            new Temporal.Duration().with({ foo: 1, bar: 2 });
+        }).toThrowWithMessage(TypeError, "Invalid duration-like object");
+    });
+
+    test("error when coercing property to number", () => {
+        for (const property of DURATION_PROPERTIES) {
+            expect(() => {
+                new Temporal.Duration().with({
+                    [property]: {
+                        valueOf() {
+                            throw new Error();
+                        },
+                    },
+                });
+            }).toThrow(Error);
+        }
+    });
+
+    test("invalid duration value", () => {
+        for (const property of DURATION_PROPERTIES) {
+            expect(() => {
+                new Temporal.Duration().with({ [property]: Infinity });
+            }).toThrowWithMessage(RangeError, "Invalid duration");
+        }
+    });
+});