来自Angular Material测试角度应用程序

Question

请有人帮助我！ 我试图测试使用Angular Material的LoginComponent，我已经在生产代码上使用了MdDialogRef，到目前为止这是我的测试类，我只想填充所有依赖项以使其运行：

import { async, ComponentFixture, TestBed } from '@angular/core/testing';
import { ReactiveFormsModule } from '@angular/forms';

import {
  MdDialogModule,
  MdDialogRef
} from '@angular/material';

import { LoginComponent } from './login.component';
import { AppMaterialModule } from 'app/module/app-material.module';
import { CustomDialogModule } from 'app/module/custom-modal/custom-dialog.module';

fdescribe('LoginComponent', () => {
  let component: LoginComponent;
  let fixture: ComponentFixture<LoginComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [LoginComponent],
      imports: [
        ReactiveFormsModule,
        MdDialogModule,
        AppMaterialModule,
        CustomDialogModule
      ],
      providers: [
        MdDialogRef
      ]
    })
      .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(LoginComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

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

我一直收到此错误：Failed: Can't resolve all parameters for MdDialogRef: (?, ?).

有什么帮助吗？谢谢！