调用 fixture.detectChanges 时未定义 enviromentService？

Question

我在运行执行此代码时出错：

   beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [ SharedTestingModule,
        TranslateModule.forRoot({
          loader: { provide: TranslateLoader, useValue: mockTranslateLoader }
        })],
      declarations: [ RequestInfoComponent, StaticContentComponent ],
      providers: [{ provide: EnvironmentService, userValue: EnvironmentService }]
    })
      .compileComponents();
  }));
  beforeEach(() => {
    fixture = TestBed.createComponent(RequestInfoComponent);
    component = fixture.componentInstance;
    componentHtml = fixture.debugElement.nativeElement;
    environmentService = fixture.debugElement.injector.get(EnvironmentService);
  });

问题是 fixture.detectChanges()。如果我删除 fixture.detectChanges() 那么一切正常，但我应该运行代码。我无法删除它。

错误是：

TypeError: this.enviromentService is undefined

这是我在组件中的代码：

import { Component, OnInit } from '@angular/core';
import { EnvironmentService } from 'app/shared/environment.service';
@Component({
  selector: 'app-request-info',
  templateUrl: './request-info.component.html',
  styles: []
})
export class RequestInfoComponent implements OnInit {
  urlPrefix: string;
  constructor(private environmentService: EnvironmentService) { }
  ngOnInit() {
    this.urlPrefix = this.environmentService.getWebContentUrlPrefix();
  }
}

Answer 1

在第一个 beforeEach 块中，您拥有的第一个提供商的类型为：

{ provide: EnvironmentService, userValue: EnvironmentService }

如果 EnvironmentService 是一种类型，请尝试将 userValue 更改为 useClass，如果它是一个值，请尝试将其更改为 useValue。

Answer 2

同意@BeetleJuice 提供的解决方案。至于你的错误：类型错误：this.enviromentService 未定义这是因为您需要按以下方式进行作业

component.environmentService = fixture.debugElement.injector.get(EnvironmentService);

调用 fixture.detectChanges 时未定义 enviromentService？

enviromentService is undefined when calling fixture.detectChanges?

javascript

jasmine

karma-runner

angular