text: test("extending function", () => {
      class A extends function () {
          this.foo = 10;
      } {}
  
      expect(new A().foo).toBe(10);
  });
  
  test("extending null", () => {
      class A extends null {}
  
      expect(Object.getPrototypeOf(A.prototype)).toBeNull();
  
      expect(() => {
          new A();
      }).toThrowWithMessage(ReferenceError, "|this| has not been initialized");
  });
  
  test("extending String", () => {
      class MyString extends String {}
  
      const ms = new MyString("abc");
      expect(ms).toBeInstanceOf(MyString);
      expect(ms).toBeInstanceOf(String);
      expect(ms.charAt(1)).toBe("b");
  
      class MyString2 extends MyString {
          charAt(i) {
              return `#${super.charAt(i)}`;
          }
      }
  
      const ms2 = new MyString2("abc");
      expect(ms2.charAt(1)).toBe("#b");
  });
  