describe("errors", () => { test("called without new", () => { expect(() => { ShadowRealm(); }).toThrowWithMessage(TypeError, "ShadowRealm constructor must be called with 'new'"); }); }); describe("normal behavior", () => { test("length is 0", () => { expect(ShadowRealm).toHaveLength(0); }); test("basic functionality", () => { const shadowRealm = new ShadowRealm(); expect(typeof shadowRealm).toBe("object"); expect(shadowRealm).toBeInstanceOf(ShadowRealm); expect(Object.getPrototypeOf(shadowRealm)).toBe(ShadowRealm.prototype); }); });