LibJS: Convert Reflect object tests to new testing framework

Libraries/LibJS/Tests/builtins/Reflect/Reflect.isExtensible.js

@@ -1,29 +1,30 @@
-load("test-common.js");
+test("length is 1", () => {
+    expect(Reflect.isExtensible).toHaveLength(1);
+});
 
-try {
-    assert(Reflect.isExtensible.length === 1);
-
-    [null, undefined, "foo", 123, NaN, Infinity].forEach(value => {
-        assertThrowsError(() => {
-            Reflect.isExtensible(value);
-        }, {
-            error: TypeError,
-            message: "First argument of Reflect.isExtensible() must be an object"
+describe("errors", () => {
+    test("target must be an object", () => {
+        [null, undefined, "foo", 123, NaN, Infinity].forEach(value => {
+            expect(() => {
+                Reflect.isExtensible(value);
+            }).toThrowWithMessage(TypeError, "First argument of Reflect.isExtensible() must be an object");
         });
     });
+});
 
-    assert(Reflect.isExtensible({}) === true);
+describe("normal behavior", () => {
+    test("regular object is extensible", () => {
+        expect(Reflect.isExtensible({})).toBeTrue();
+    });
 
-    var o = {};
-    o.foo = "foo";
-    assert(o.foo === "foo");
-    assert(Reflect.isExtensible(o) === true);
-    Reflect.preventExtensions(o);
-    o.bar = "bar";
-    assert(o.bar === undefined);
-    assert(Reflect.isExtensible(o) === false);
+    test("global object is extensible", () => {
+        expect(Reflect.isExtensible(globalThis)).toBeTrue();
+    });
 
-    console.log("PASS");
-} catch (e) {
-    console.log("FAIL: " + e);
-}
+    test("regular object is not extensible after preventExtensions()", () => {
+        var o = {};
+        expect(Reflect.isExtensible(o)).toBeTrue();
+        Reflect.preventExtensions(o);
+        expect(Reflect.isExtensible(o)).toBeFalse();
+    });
+});