ladybird/Libraries/LibJS/Tests/builtins/Reflect/Reflect.defineProperty.js

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

describe("errors", () => {
  test("target must be an object", () => {
    [null, undefined, "foo", 123, NaN, Infinity].forEach(value => {
      expect(() => {
        Reflect.defineProperty(value);
      }).toThrowWithMessage(
        TypeError,
        "First argument of Reflect.defineProperty() must be an object"
      );
    });
  });

  test("descriptor must be an object", () => {
    [null, undefined, "foo", 123, NaN, Infinity].forEach(value => {
      expect(() => {
        Reflect.defineProperty({}, "foo", value);
      }).toThrowWithMessage(TypeError, "Descriptor argument is not an object");
    });
  });
});

describe("normal behavior", () => {
  test("initial value and non-writable", () => {
    var o = {};

    expect(o.foo).toBeUndefined();
    expect(Reflect.defineProperty(o, "foo", { value: 1, writable: false })).toBeTrue();
    expect(o.foo).toBe(1);
    o.foo = 2;
    expect(o.foo).toBe(1);
  });

  test("initial value and writable", () => {
    var o = {};

    expect(o.foo).toBeUndefined();
    expect(Reflect.defineProperty(o, "foo", { value: 1, writable: true })).toBeTrue();
    expect(o.foo).toBe(1);
    o.foo = 2;
    expect(o.foo).toBe(2);
  });

  test("can redefine value of configurable, writable property", () => {
    var o = {};

    expect(o.foo).toBeUndefined();
    expect(
      Reflect.defineProperty(o, "foo", { value: 1, configurable: true, writable: true })
    ).toBeTrue();
    expect(o.foo).toBe(1);
    expect(Reflect.defineProperty(o, "foo", { value: 2 })).toBeTrue();
    expect(o.foo).toBe(2);
  });

  test("can redefine value of configurable, non-writable property", () => {
    var o = {};

    expect(o.foo).toBeUndefined();
    expect(
      Reflect.defineProperty(o, "foo", { value: 1, configurable: true, writable: false })
    ).toBeTrue();
    expect(o.foo).toBe(1);
    expect(Reflect.defineProperty(o, "foo", { value: 2 })).toBeTrue();
    expect(o.foo).toBe(2);
  });

  test("cannot redefine value of non-configurable, non-writable property", () => {
    var o = {};

    expect(o.foo).toBeUndefined();
    expect(
      Reflect.defineProperty(o, "foo", { value: 1, configurable: false, writable: false })
    ).toBeTrue();
    expect(o.foo).toBe(1);
    expect(Reflect.defineProperty(o, "foo", { value: 2 })).toBeFalse();
    expect(o.foo).toBe(1);
  });
});