无法监视另一个 class 中的 class 实例

Question

我正在控制器 class 中实例化服务 class，控制器中使用了服务的 log 方法。

在 spec 文件中，我在 log 方法上添加了 spy，但是没有调用 spy。

这是我的代码

test.service.ts

export class TestService {
  public log(msg: string): void {
    console.log(msg);
  }
}

test.controller.ts

import { TestService } from "../service/cart.service";

export class CartController {
  private testService: TestService;

  constructor() {
    this.testService = new TestService();
  }
  public testFx():void {
    this.testService.log("Here is a dummy msg.")
  }
}

test.controller.spec.ts

import { TestController } from "./test.controller";
import { TestService } from "./test.service";
describe("Testing controller", () => {
  private testController: TestController = new TestController();
  private testService: TestService = new TestService();

  it ("test function", () => {
    spyOn(testService, "log");
    testController.testFx();
    expect(testService.log).toHaveBeenCalled();
  });
})

错误：- Expected spy log to have been called.

Answer 1

而不是创建一个新的 class 实例，

 private testController: TestController = new TestController();
 private testService: TestService = new TestService();

 it ("test function", () => {
 spyOn(testService, "log");

你可以使用 escape hatch 。

试试这个：

 private testController: TestController = new TestController();
 it ("test function", () => {
 spyOn(testController["testService"], "log");

由于 private, protected and public 是 typescript 语法糖的概念，因此当代码编译为 javascript 时它与它无关。更具解释性的答案是 .

无法监视另一个 class 中的 class 实例

Unable to spy on a class instance inside another class

unit-testing

mocking

node.js

jasmine

jasmine-node