Angular如何测试MatDialog函数-打开和关闭

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

describe('MyComponent', () => {
  let component: MyComponent;
  let fixture: ComponentFixture<MyComponent>;
  let matDialog: MatDialog;

  beforeEach(async () => {
    await TestBed.configureTestingModule({
      declarations: [MyComponent],
      providers: [MatDialog]
    }).compileComponents();
  });

  beforeEach(() => {
    fixture = TestBed.createComponent(MyComponent);
    component = fixture.componentInstance;
    matDialog = TestBed.inject(MatDialog);
    fixture.detectChanges();
  });

  it('should open and close MatDialog', () => {
    spyOn(matDialog, 'open').and.callThrough();
    spyOn(matDialog, 'closeAll').and.callThrough();

    component.openDialog();
    expect(matDialog.open).toHaveBeenCalled();

    component.closeDialog();
    expect(matDialog.closeAll).toHaveBeenCalled();
  });
});