如何使用业力测试垫选择组件

Question

我的组件：

@Component({
  selector: 'p-dropdown',
  template: `
<mat-form-field *ngIf="settings">
  <mat-select [value]="settings.selected" [compareWith]="compareFn" [placeholder]="placeholder">
      <mat-option *ngFor="let option of settings.options" [value]="option"> {{option.name}} </mat-option>
  </mat-select>
</mat-form-field>

我的测试：

fdescribe('Drodown Component', () => {
  let component: TestHostComponent;
  let fixture: ComponentFixture<TestHostComponent>;
  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [TestHostComponent, DropdownComponent],
      imports:[materialModule,BrowserAnimationsModule]
    }).compileComponents();
  })); 
  beforeEach(() => {
    fixture = TestBed.createComponent(TestHostComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });
  fit('should show placeholder', () => {
    const el: HTMLElement = fixture.nativeElement;
    fixture.detectChanges();
    const p = el.querySelector('.mat-form-field-label');
    expect(p.textContent).toEqual('name2');
  });
});
@Component({
  selector: `host-component`,
  template: `<p-dropdown [settings]="settings"></p-dropdown>`
})
class TestHostComponent {
  settings = {options:[{_id:1,name:'name1'}, {_id:2,name:'name2'}], selected:{_id:2,name:'name2'}}
}

“ p-dropdown”在投​​放时效果很好，但由于某些原因，在我的测试中不起作用。 在调试中，我也可以看到p-dropdown设置，所以我不明白问题出在哪里。