如何编写简单的测试来检查Angular 2中MatDialog的行为？

// my-dialog.component.ts
import { Component } from '@angular/core';

@Component({
  selector: 'app-my-dialog',
  template: `<p>这是一个对话框</p>`,
})
export class MyDialogComponent {}

// my-dialog.component.spec.ts
import { ComponentFixture, TestBed } from '@angular/core/testing';
import { MatDialog } from '@angular/material/dialog';
import { MyDialogComponent } from './my-dialog.component';

describe('MyDialogComponent', () => {
  let component: MyDialogComponent;
  let fixture: ComponentFixture<MyDialogComponent>;
  let dialogMock: any;

  beforeEach(async () => {
    dialogMock = jasmine.createSpyObj('MatDialog', ['open']);
    await TestBed.configureTestingModule({
      declarations: [ MyDialogComponent ],
      providers: [
        { provide: MatDialog, useValue: dialogMock }
      ]
    })
    .compileComponents();
  });

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

  it('should open dialog on button click', () => {
    const button = fixture.nativeElement.querySelector('button');
    button.click();
    expect(dialogMock.open).toHaveBeenCalledWith(MyDialogComponent);
  });
});