Everywhere: Hoist the Libraries folder to the top-level

Author: https://github.com/trflynn89
Commit: 93712b24bf
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2256
Reviewed-by: https://github.com/sideshowbarker

Libraries/LibJS/Tests/builtins/Proxy/Proxy.handler-has.js

@@ -0,0 +1,104 @@
+describe("[[Has]] trap normal behavior", () => {
+    test("forwarding when not defined in handler", () => {
+        expect("foo" in new Proxy({}, { has: null })).toBeFalse();
+        expect("foo" in new Proxy({}, { has: undefined })).toBeFalse();
+        expect("foo" in new Proxy({}, {})).toBeFalse();
+    });
+
+    test("correct arguments supplied to trap", () => {
+        let o = {};
+        let p = new Proxy(o, {
+            has(target, prop) {
+                expect(target).toBe(o);
+                expect(prop).toBe("foo");
+                return true;
+            },
+        });
+
+        "foo" in p;
+    });
+
+    test("correct arguments passed to trap even for number", () => {
+        let o = {};
+        let p = new Proxy(o, {
+            has(target, prop) {
+                expect(target).toBe(o);
+                expect(prop).toBe("1");
+                return true;
+            },
+        });
+
+        1 in p;
+    });
+
+    test("conditional return", () => {
+        let o = {};
+        let p = new Proxy(o, {
+            has(target, prop) {
+                if (target.checkedFoo) return true;
+                if (prop === "foo") target.checkedFoo = true;
+                return false;
+            },
+        });
+
+        expect("foo" in p).toBeFalse();
+        expect("foo" in p).toBeTrue();
+    });
+});
+
+describe("[[Has]] invariants", () => {
+    test("cannot return false if the property exists and is non-configurable", () => {
+        let o = {};
+        Object.defineProperty(o, "foo", { configurable: false });
+
+        p = new Proxy(o, {
+            has() {
+                return false;
+            },
+        });
+
+        expect(() => {
+            "foo" in p;
+        }).toThrowWithMessage(
+            TypeError,
+            "Proxy handler's has trap violates invariant: a property cannot be reported as non-existent if it exists on the target as a non-configurable property"
+        );
+    });
+
+    test("cannot return false if the property exists and the target is non-extensible", () => {
+        let o = {};
+        Object.defineProperty(o, "foo", { value: 10, configurable: true });
+
+        let p = new Proxy(o, {
+            has() {
+                return false;
+            },
+        });
+
+        Object.preventExtensions(o);
+
+        expect(() => {
+            "foo" in p;
+        }).toThrowWithMessage(
+            TypeError,
+            "Proxy handler's has trap violates invariant: a property cannot be reported as non-existent if it exists on the target and the target is non-extensible"
+        );
+    });
+});
+
+test("Proxy handler that has the Proxy itself as its prototype", () => {
+    const handler = {};
+    const proxy = new Proxy({}, handler);
+    handler.__proto__ = proxy;
+    expect(() => {
+        "foo" in proxy;
+    }).toThrowWithMessage(InternalError, "Call stack size limit exceeded");
+});
+
+test("Proxy that has the Proxy itself as its prototype", () => {
+    const proxy = new Proxy({}, {});
+    proxy.__proto__ = Object.create(proxy);
+    expect(() => {
+        "foo" in proxy;
+    }).toThrowWithMessage(InternalError, "Call stack size limit exceeded");
+});