如何对服务构造函数中调用的函数进行单元测试？

Question

如何在服务的规范文件中测试构造函数中调用的函数？例如：

@Injectable({
    providedIn: 'root'
})
export class myService {
  

    constructor() {
       this.myFunction();
    }

    myFunction(){}
}

那么我如何测试我的函数是否被调用呢？

beforeEach(() => {
TestBed.configureTestingModule({});
    service = TestBed.get(myService);

我无法在 testbed.get 之前监视服务，我尝试过：

beforeEach(() => {
TestBed.configureTestingModule({});
    service = TestBed.get(myService);

但这并不能说明间谍没有被召唤！

非常感激任何的帮助。

Answer 1

使用spyOn(obj, methodName) \xe2\x86\x92 {Spy}myFunction来监视MyService.prototype.

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例如

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service.ts:

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import { Injectable } from \'@angular/core\';\n\n@Injectable({\n  providedIn: \'root\',\n})\nexport class MyService {\n  constructor() {\n    this.myFunction();\n  }\n\n  myFunction() {}\n}\n

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service.test.ts:

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import { MyService } from \'./service\';\n\ndescribe(\'63819030\', () => {\n  it(\'should pass\', () => {\n    const myFunctionSpy = spyOn(MyService.prototype, \'myFunction\').and.stub();\n    const service = new MyService();\n    expect(myFunctionSpy).toHaveBeenCalledTimes(1);\n  });\n});\n

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