Convert a regular element into a DebugElement within an Angular framework

Recently, I was working on testing an Angular Component which was going smoothly until I encountered a challenging issue that has been perplexing me for days. My main objective was to test whether the method "ajouterCompteurALaCampagne" is being called when inserting a row. In order to achieve this, I attempted to access the dx-data-grid DOM element to emit the "onRowInserting" event. However, this is where the problem arises - I found myself unable to access that element as a DebugElement; only as a nativeElement. Consequently, I faced difficulty in emitting the onRowInserting event and confirming if the desired method was being invoked or not. So, my query is: "Is there a way to 'cast' the nativeElement so I can have access to the DebugElement properties?"

HTML CODE

<dx-tab-panel
  [height]="'auto'"
  [dataSource]="tabs"
  [selectedIndex]="0"
  [loop]="false"
  [animationEnabled]="true">

 
  <div *dxTemplate="let data of 'compteursTemplate'">
    <dx-data-grid
      #tabCompteurCampagne
      id = 'liste-compteur'
      [showBorders]="true"
      [dataSource]="listeCompteur"
      (onRowInserting)="ajouterCompteurALaCampagne($event)"
      (onRowRemoving)="supprimerCompteurCampagne($event)"
      (onRowUpdated)="modifierCompteurCampagne($event)">
    ...</dx-data-grid>
  ...</div>
...<dx-tab-panel>

TYPESCRIPT CODE

it("should call the method 'ajouterCompteurALaCampagne' once the event is emitted", async(()=>{
  let spy_ajouterCompteurALaCampagne = spyOn(component, "ajouterCompteurALaCampagne");
  let dxTabPanelElement = fixture.debugElement.query(
    By.directive(DxTabPanelComponent)
  );
 let dxGridElement = dxTabPanelElement.nativeElement.querySelector('#liste-compteur');
  dxGridElement.dispatchEvent(new Event("rowInserting")); //the event is not emmited
  expect(spy_ajouterCompteurALaCampagne).toHaveBeenCalledTimes(1);
  }));
 });

Answer №1

After some troubleshooting, I have managed to resolve this issue. Thank you to everyone who contributed their insights. Here is the snippet of code that did the trick:

it("should call the method 'ajouterCompteurALaCampagne' once the event is emitted", async(()=>{
let spy_ajouterCompteurALaCampagne = spyOn(component, "ajouterCompteurALaCampagne");
let dxGridElement = fixture.nativeElement.querySelector("dx-data-grid");
console.log(dxGridElement);
dxGridElement.dispatchEvent(new Event("onRowInserting"));
fixture.detectChanges();
expect(spy_ajouterCompteurALaCampagne).toHaveBeenCalledTimes(1);

}));

I hope this solution proves beneficial to someone facing a similar challenge in the future.

Answer №2

Is there a reason why you are not utilizing the debugElement? In such scenarios, I believe you can make use of triggerEventHandler which is a feature from Angular.

Give this a shot:

it("should execute the method 'ajouterCompteurALaCampagne' once the event is triggered", async(()=>{
  let spy_ajouterCompteurALaCampagne = spyOn(component, "ajouterCompteurALaCampagne");
  // utilize fixture.
  let dxGridElement = fixture.debugElement.query(By.css('dx-data-grid'));
  dxGridElement.triggerEventHandler('onRowInserting', { /* here you can simulate the $event object */ });
  expect(spy_ajouterCompteurALaCampagne).toHaveBeenCalledTimes(1);
}));

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