Angular2 jasmine unit test component with third party directive

Question

Component is https://github.com/valor-software/ngx-bootstrap dropdown.

in template i have this:

    <span dropdown placement="bottom right">
      <a id="droplist-label" href="javascript:void(0)" dropdownToggle>
          <span>{{conf.title}}</span>
      </a>
      <ul class="dropdown-menu pull-right" *dropdownMenu>
        <li *ngFor="let item of items">
          <a class="dropdown-item" (click)="listClick(item.value)" href="javascript:void(0)">{{item.label}}</a>
        </li>
      </ul>
    </span>

The ul is not added until the label is clicked - therefor i cannot access it in the test.

Calling click:

let droplist = fixture.debugElement.query(By.css('#droplist-label')).nativeElement;
droplist.click();

Does not work - if i try to look for dropdown-menu it is empty:

it('should test if droplist has title',  async(() => {
    fixture.detectChanges();
    let droplist = fixture.debugElement.query(By.css('#droplist-label')).nativeElement;
    droplist.click();

    fixture.whenStable().then(() => {
        let droplistOptions = fixture.debugElement.queryAll(By.css('.dropdown-item'));
        expect(droplistOptions.length).toBeGreaterThan(0);
    });
}));

The directive has a hostlistener for click event it seems - how can i trigger it so the ul becomes available?

Answer 1

I finally solved the same pb using fakeAsync() :

it('should render submenus', fakeAsync(() => {

  fixture.detectChanges(); // update the view

  // trig submenus opening
  let toggleButtons = fixture.debugElement.nativeElement.querySelectorAll('[dropdownToggle]');
  toggleButtons.forEach(b => b.click());


  tick();                  // wait for async tasks to end
  fixture.detectChanges(); // update the view

  // then count how many items you got for each submenus.
  let droplistOptions1= fixture.debugElement.nativeElement.querySelectorAll('#first-ul > li')
  let droplistOptions2= fixture.debugElement.nativeElement.querySelectorAll('#second-ul > li')
  let droplistOptions3= fixture.debugElement.nativeElement.querySelectorAll('#third-ul > li')
  expect(droplistOptions1.length).toEqual(3);
  expect(droplistOptions2.length).toEqual(5);
  expect(droplistOptions3.length).toEqual(2);
}));

But I am sure it is possible to do it with an async() : I guess you only missed a fixture.detectChanges() at the beginning of the fixture.whenStable().then(...) in your initial try.

---

Also, remember to import the BsDropdownModule into your testbed :

import { BsDropdownModule} from 'ngx-bootstrap/dropdown';
...
TestBed.configureTestingModule({
  imports: [
    BsDropdownModule.forRoot(),
  ],
  ...
});

Answer 2

This is the solution i came up with to the problem above - using children to get the elements inside.

it('should test if droplist has listed correct values',  async(() => {
    comp.isOpen = true;
    fixture.detectChanges();
    fixture.whenStable().then(() => {
        let droplist = fixture.debugElement.query(By.css('.dropdown-menu'));
        fixture.detectChanges();
        expect(droplist.children.length).toBeGreaterThan(0);
        let i = 0;
        for(let item of droplist.children) {
            let anchorElement = item.children[0].nativeElement;
            expect(anchorElement.innerText).toBe(droplistItems[i].label);
            expect(anchorElement.getAttribute('data-value')).toBe(droplistItems[i].value);
            i++;
        }
    });
}));