Everywhere: Hoist the Libraries folder to the top-level

Author: https://github.com/trflynn89
Commit: https://github.com/LadybirdBrowser/ladybird/commit/93712b24bf2
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2256
Reviewed-by: https://github.com/sideshowbarker

Libraries/LibJS/Tests/builtins/JSON/JSON.stringify.js

@@ -0,0 +1,99 @@
+describe("correct behavior", () => {
+    test("length", () => {
+        expect(JSON.stringify).toHaveLength(3);
+    });
+
+    test("basic functionality", () => {
+        [
+            [5, "5"],
+            [undefined, undefined],
+            [null, "null"],
+            [NaN, "null"],
+            [-NaN, "null"],
+            [Infinity, "null"],
+            [-Infinity, "null"],
+            [true, "true"],
+            [false, "false"],
+            ["test", '"test"'],
+            [new Number(5), "5"],
+            [new Boolean(false), "false"],
+            [new String("test"), '"test"'],
+            [() => {}, undefined],
+            [[1, 2, "foo"], '[1,2,"foo"]'],
+            [{ foo: 1, bar: "baz", qux() {} }, '{"foo":1,"bar":"baz"}'],
+            [
+                {
+                    var1: 1,
+                    var2: 2,
+                    toJSON(key) {
+                        let o = this;
+                        o.var2 = 10;
+                        return o;
+                    },
+                },
+                '{"var1":1,"var2":10}',
+            ],
+        ].forEach(testCase => {
+            expect(JSON.stringify(testCase[0])).toEqual(testCase[1]);
+        });
+    });
+
+    test("serialize BigInt with a toJSON property", () => {
+        Object.defineProperty(BigInt.prototype, "toJSON", {
+            configurable: true, // Allows deleting this property at the end of this test case.
+            get() {
+                "use strict";
+                return () => typeof this;
+            },
+        });
+
+        expect(JSON.stringify(1n)).toBe('"bigint"');
+        delete BigInt.prototype.toJSON;
+    });
+
+    test("ignores non-enumerable properties", () => {
+        let o = { foo: "bar" };
+        Object.defineProperty(o, "baz", { value: "qux", enumerable: false });
+        expect(JSON.stringify(o)).toBe('{"foo":"bar"}');
+    });
+
+    test("ignores symbol properties", () => {
+        let o = { foo: "bar" };
+        let sym = Symbol("baz");
+        o[sym] = "qux";
+        expect(JSON.stringify(o)).toBe('{"foo":"bar"}');
+    });
+
+    test("escape surrogate codepoints in strings", () => {
+        expect(JSON.stringify("\ud83d\ude04")).toBe('"😄"');
+        expect(JSON.stringify("\ud83d")).toBe('"\\ud83d"');
+        expect(JSON.stringify("\ude04")).toBe('"\\ude04"');
+        expect(JSON.stringify("\ud83d\ud83d\ude04\ud83d\ude04\ude04")).toBe('"\\ud83d😄😄\\ude04"');
+        expect(JSON.stringify("\ude04\ud83d\ude04\ud83d\ude04\ud83d")).toBe('"\\ude04😄😄\\ud83d"');
+    });
+});
+
+describe("errors", () => {
+    test("cannot serialize BigInt", () => {
+        expect(() => {
+            JSON.stringify(5n);
+        }).toThrow(TypeError, "Cannot serialize BigInt value to JSON");
+    });
+
+    test("cannot serialize circular structures", () => {
+        let bad1 = {};
+        bad1.foo = bad1;
+        let bad2 = [];
+        bad2[5] = [[[bad2]]];
+
+        let bad3a = { foo: "bar" };
+        let bad3b = [1, 2, bad3a];
+        bad3a.bad = bad3b;
+
+        [bad1, bad2, bad3a].forEach(bad => {
+            expect(() => {
+                JSON.stringify(bad);
+            }).toThrow(TypeError, "Cannot stringify circular object");
+        });
+    });
+});