我的单元测试源代码：import { Component } from '@angular/core';

import { waitForAsync, ComponentFixture, TestBed } from '@angular/core/testing';

import { By } from '@angular/platform-browser';

import { FocusDirective } from './focus.directive';

import { KeyboardFocusService } from './services';

/*

 After cxFocus is enhanced with refreshFocus feature, an element will be focused twice when the page is displayed for the FIRST time:  

 1. in ngOnChanges hook

 2. in ngAfterViewInit hook

 

 Once the page is rendered, all subsequent operations will only cause element to be focused once in ngOnChanges, because ngAfterViewInit then will not be triggered any more.  

*/

const ELEMENT_FOCUSED_TIME = 2;

@Component({

 selector: 'cx-host',

 template: `

   id="a"

   [cxFocus]="{ autofocus: true, refreshFocus: modelA }"

 >

`,

})

class MockComponent {

 modelA = 'A';

 modelB = 'B';

}

class MockKeyboardFocusService {

 get() {}

 set() {}

 shouldFocus() {}

 getPersistenceGroup() {}

 findFirstFocusable() {}

 hasPersistedFocus() {}

}

describe('FocusDirective', () => {

 let component: MockComponent;

 let fixture: ComponentFixture;

 let keyboardFocusService: KeyboardFocusService;

 beforeEach(

   waitForAsync(() => {

     TestBed.configureTestingModule({

       declarations: [FocusDirective, MockComponent],

       providers: [

         {

           provide: KeyboardFocusService,

           useClass: MockKeyboardFocusService,

         },

       ],

     }).compileComponents();

     fixture = TestBed.createComponent(MockComponent);

     component = fixture.componentInstance;

     keyboardFocusService = TestBed.inject(KeyboardFocusService);

   })

 );

 it('should be created', () => {

   expect(component).toBeTruthy();

 });

 it('should default tabindex to -1', () => {

   const el: HTMLElement = fixture.debugElement.query(By.css('#a'))

     .nativeElement;

   fixture.detectChanges();

   expect(el.getAttribute('tabindex')).toEqual('-1');

 });

 it('should focus element marked with autofocus = true', () => {

   const el: HTMLElement = fixture.debugElement.query(By.css('#a'))

     .nativeElement;

   spyOn(keyboardFocusService, 'findFirstFocusable').and.returnValue(el);

   fixture.detectChanges();

   expect(document.activeElement.id).toEqual('a');

 });

 it('should only refresh focus with change on configured attribute', () => {

   const el: HTMLElement = fixture.debugElement.query(By.css('#a'))

     .nativeElement;

   let spiedFirstFocusable = spyOn(

     keyboardFocusService,

     'findFirstFocusable'

   ).and.returnValue(el);

   fixture.detectChanges();

   expect(document.activeElement.id).toEqual('a');

   expect(spiedFirstFocusable).toHaveBeenCalledTimes(ELEMENT_FOCUSED_TIME);

   component.modelB = '1';

   fixture.detectChanges();

   expect(spiedFirstFocusable).toHaveBeenCalledTimes(ELEMENT_FOCUSED_TIME);

   component.modelA = '1';

   fixture.detectChanges();

   expect(spiedFirstFocusable).toHaveBeenCalledTimes(ELEMENT_FOCUSED_TIME + 1);

 });

});执行到refreshView时，由于之前已经执行过fixture.detectChange, 因此第7225行hooksInitPhaseCompleted这个标志位为true了，因此会执行AfterViewChecked hook，而不是else 分支内的AfterViewInit hook: