LibJS: Implement Object.defineProperties()

Userland/Libraries/LibJS/Tests/builtins/Object/Object.defineProperties.js

@@ -0,0 +1,57 @@
+test("length is 2", () => {
+    expect(Object.defineProperties).toHaveLength(2);
+});
+
+describe("errors", () => {
+    test("non-object argument", () => {
+        expect(() => Object.defineProperties(42, {})).toThrowWithMessage(
+            TypeError,
+            "Object argument is not an object"
+        );
+    });
+});
+
+describe("normal behavior", () => {
+    test("returns given object", () => {
+        const o = {};
+        expect(Object.defineProperties(o, {})).toBe(o);
+    });
+
+    test("defines given properties on object", () => {
+        const properties = {
+            foo: {
+                writable: true,
+                configurable: true,
+                value: "foo",
+            },
+            bar: {
+                enumerable: true,
+                value: "bar",
+            },
+            baz: {
+                get() {},
+                set() {},
+            },
+        };
+        const o = Object.defineProperties({}, properties);
+        expect(Object.getOwnPropertyNames(o)).toEqual(["foo", "bar", "baz"]);
+        expect(Object.getOwnPropertyDescriptor(o, "foo")).toEqual({
+            value: "foo",
+            writable: true,
+            enumerable: false,
+            configurable: true,
+        });
+        expect(Object.getOwnPropertyDescriptor(o, "bar")).toEqual({
+            value: "bar",
+            writable: false,
+            enumerable: true,
+            configurable: false,
+        });
+        expect(Object.getOwnPropertyDescriptor(o, "baz")).toEqual({
+            get: properties.baz.get,
+            set: properties.baz.set,
+            enumerable: false,
+            configurable: false,
+        });
+    });
+});