Jest/Typescript：在 jest 和 Typescript 中包含私有成员的模拟类依赖项

上下文：我有依赖于类 A 的类 B。我想测试类 B 的方法，该方法在内部调用类 A 的方法。现在，我想通过模拟类 A 对类 B 的方法进行单元测试。

Note 1: A 类有一些私有成员

Note 2: A类没有接口

这是我的代码结构：

class Base {

  someMethod() {
     return "Hello ";
  }

}


class A {

  private _baseClassImpl: Base;

  constructor(baseClassImpl: Base) {
     this._baseClassImpl = baseClassImpl;
  }

  getSomething() {     
     return this._baseClassImpl.someMethod() + " Something";
  }
}


class B {
  constructor(objectOfClassA: A) {
      this._objectOfClassA = objectOfClassA;

 }

 functionOfClassBToTest() {
     const returnValueFromClassA = this._objectOfClassA.getSomething();

     return returnValueFromClassA;
 }
}

到目前为止我已经尝试过：

听取建议后我之前的帖子 https://stackoverflow.com/questions/70635377/jest-typescript-mock-class-dependencies-in-jest-and-typescript我尝试编写这样的测试：

const getSomethingMock = jest.fn().mockImplementation(() => {
    return "Mock value";
});

const mockA = jest.Mocked<A> = {
   getSomething: getSomethingMock
};

test("test functionOfClassBToTest", () => {
   const classBToTest = new B(mockA);
   
   expect(classBToTest.functionofClassBToTest.toStrictEqual("Hello Something");

});

上面的代码给了我这个错误：

Type '{ getSomething: jest.Mock<any, any>; }' is not assignable is not assignable to type 'Mocked<A>'. 
Type '{ getSomething: jest.Mock<any, any>; }' is missing the following properties from type 'A': _baseClassImpl

当我尝试为 _baseClassImpl 提供模拟值时，如下所示：

const baseClassMock = jest.Mocked<Base> = {
  someMethod: jest.fn()
};

const getSomethingMock = jest.fn().mockImplementation(() => {
    return "Mock value";
});

const mockA = jest.Mocked<A> = {
   getSomething: getSomethingMock,
   _baseClassImpl: baseClassMock
};

打字稿给了我这个错误：

Type '{ getSomething: jest.Mock<any, any>; _baseClassImpl: jest.Mocked<Base>; }' is not assignable is not assignable to type 'Mocked<A>'. 

Type '{ getSomething: jest.Mock<any, any>; _baseClassImpl: jest.Mocked<Base>; }' is not assignable is not assignable to type 'A'. 

Property '_baseClassImpl' is private in type 'A' but not in type '{ getSomething: jest.Mock<any, any>; _baseClassImpl: jest.Mocked<Base>; }'

我已经尝试过我的答案以前的SO帖子 https://stackoverflow.com/questions/70635377/jest-typescript-mock-class-dependencies-in-jest-and-typescript但在与私人成员一起上课的情况下它不起作用。

一些注意事项：

Note 1: A 类包含私有成员

Note 2: A类没有接口

Note 3: 我不想在我的测试函数中初始化 A 类的对象。我只想嘲笑班级。

经过一些尝试和帮助github 仓库 https://github.com/stevenulibarri/jest-typescript-mock-reference，我能够解决这个问题。

这是供参考的代码：

测试 functionOfClassBToTest ：

//Note: this can be also written as : const mockA = new (<any>A)() as jest.Mocked<A>;
const mockA = new (<new () => A>A)() as jest.Mocked<A>;

mockA.getSomething = jest.fn();

test("test functionOfClassBToTest", () => {
   
   mockA.getSomething.mockReturnValueOnce("Hello Something");

   const classBToTest = new B(mockA);
   
   expect(classBToTest.functionofClassBToTest.toStrictEqual("Hello Something");

});