Angular 2在Karma Jasmine测试中实例化parent中的全局注入器

// app.module.ts 或者 app.component.ts
import { Injector } from '@angular/core';

export let globalInjector: Injector;

@NgModule({
  // ...
})
export class AppModule {
  constructor(private injector: Injector) {
    globalInjector = this.injector;
  }
}

import { TestBed } from '@angular/core/testing';
import { MyService } from './my.service';
import { globalInjector } from './app.module'; // 或者 app.component.ts

describe('MyService', () => {
  let myService: MyService;

  beforeEach(() => {
    // 使用全局注入器获取服务实例
    myService = globalInjector.get(MyService);
  });

  it('should be created', () => {
    expect(myService).toBeTruthy();
  });

  // ... 其他测试
});

// my.service.ts
import { Injectable } from '@angular/core';
import { AnotherService } from './another.service';

@Injectable({
  providedIn: 'root'
})
export class MyService {
  constructor(private anotherService: AnotherService) {}

  doSomething() {
    return this.anotherService.doAnotherThing();
  }
}

import { TestBed } from '@angular/core/testing';
import { MyService } from './my.service';
import { AnotherService } from './another.service';
import { globalInjector } from './app.module';

describe('MyService', () => {
  let myService: MyService;

  beforeEach(() => {
    // 使用全局注入器获取服务实例
    myService = globalInjector.get(MyService);
    spyOn(globalInjector.get(AnotherService), 'doAnotherThing').and.returnValue('mocked result');
  });

  it('should call doAnotherThing on AnotherService', () => {
    const result = myService.doSomething();
    expect(result).toBe('mocked result');
  });
});