得到 NullInjectorError 的错误：没有 HttpClient 的提供者！在角度测试中

如何解决得到 NullInjectorError 的错误：没有 HttpClient 的提供者！在角度测试中

在 angular 中运行 ng 测试时，我收到以下错误 SidebarComponent > 应该创建 NullInjectorError: R3InjectorError(DynamicTestModule)[AuthserviceService -> HttpClient -> HttpClient]: NullInjectorError: 没有 HttpClient 的提供者！

sidebar.component.spec.ts

import { async,ComponentFixture,Testbed } from '@angular/core/testing';

import { SidebarComponent } from './sidebar.component';

describe('SidebarComponent',() => {
  let component: SidebarComponent;
  let fixture: ComponentFixture<SidebarComponent>;

  beforeEach(async(() => {
    Testbed.configureTestingModule({
      declarations: [ SidebarComponent ]
    })
    .compileComponents();
  }));

  beforeEach(() => {
    fixture = Testbed.createComponent(SidebarComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should create',() => {
    expect(component).toBeTruthy();
  });
});

app.module.ts

import { browserModule } from '@angular/platform-browser';
import { AppRoutingModule } from './app-routing.module';
import { NgModule,Input,Output,EventEmitter} from '@angular/core';
import { HttpClientModule } from '@angular/common/http';
import { NgbModule } from '@ng-bootstrap/ng-bootstrap';
import { browserAnimationsModule } from '@angular/platform-browser/animations';
import { ChartsModule,ThemeService } from 'ng2-charts';
import { AuthserviceService } from './authservice.service';
import { DashboardService } from './dashboard.service';
import { AppComponent } from './app.component';
import { NavbarComponent } from './shared/navbar/navbar.component';
import { SidebarComponent } from './shared/sidebar/sidebar.component';
import { FooterComponent } from './shared/footer/footer.component';
import { DashboardComponent } from './main/dashboard/dashboard.component';
import { FormsModule,ReactiveFormsModule } from '@angular/forms';
import { SpinnerComponent } from './shared/spinner/spinner.component';
import { AboutComponent } from './main/about/about.component';
import { NotificationsComponent } from './main/notifications/notifications.component';
import { LoginComponent } from './login/login.component';
import { MainComponent } from './main/main.component';
import { UserinfoComponent } from './userinfo/userinfo.component';
import { ReportComponent } from './main/report/report.component';
import { Shared } from './shared.service';

@NgModule({
  declarations: [
    AppComponent,NavbarComponent,SidebarComponent,FooterComponent,DashboardComponent,SpinnerComponent,AboutComponent,NotificationsComponent,LoginComponent,MainComponent,UserinfoComponent,ReportComponent,],imports: [
    browserModule,AppRoutingModule,NgbModule,browserAnimationsModule,FormsModule,ReactiveFormsModule,ChartsModule,HttpClientModule,providers: [ThemeService,AuthserviceService,DashboardService,Shared],bootstrap: [AppComponent]
})
export class AppModule { }

我是这个测试的新手，谁能帮我。

解决方法

您必须使用您需要的所有导入和提供程序设置测试。当您使用 ng test 启动测试套件时，每个规范都是独立的，并且不使用 AppModule，因此您必须重新设置测试用例的所有内容。

在这种特殊情况下，您应该将 HttpClientTestingModule 添加到测试用例中的导入数组中，就在声明数组的下方。之后你可能会遇到其他错误，你必须不断添加模块和提供程序直到它工作，错误消息将有助于找到错误。

此链接可能有帮助：https://angular.io/guide/testing-components-scenarios