ladybird/Userland/Libraries/LibJS/Tests/builtins/Reflect/Reflect.apply.js

test("length is 3", () => {
    expect(Reflect.apply).toHaveLength(3);
});

describe("errors", () => {
    test("target must be a function", () => {
        [null, undefined, "foo", 123, NaN, Infinity, {}].forEach(value => {
            expect(() => {
                Reflect.apply(value);
            }).toThrowWithMessage(TypeError, `${value} is not a function`);
        });
    });

    test("arguments list must be an object", () => {
        [null, undefined, "foo", 123, NaN, Infinity].forEach(value => {
            expect(() => {
                Reflect.apply(() => {}, undefined, value);
            }).toThrowWithMessage(TypeError, `${value} is not an object`);
        });
    });
});

describe("normal behavior", () => {
    test("calling built-in functions", () => {
        expect(Reflect.apply(String.prototype.charAt, "foo", [0])).toBe("f");
        expect(Reflect.apply(Array.prototype.indexOf, ["hello", 123, "foo", "bar"], ["foo"])).toBe(
            2
        );
    });

    test("|this| argument is forwarded to called function", () => {
        function Foo(foo) {
            this.foo = foo;
        }

        var o = {};
        expect(o.foo).toBeUndefined();
        Reflect.apply(Foo, o, ["bar"]);
        expect(o.foo).toBe("bar");
    });
});