Unit test Angular Material Dialog - How to include MAT_DIALOG_DATA

Question

I am trying to unit test this material dialog to test if the template is rendering the right injected object. The component works fine when used properly

Component - The Dialog

export class ConfirmationDialogComponent {

  constructor(@Inject(MAT_DIALOG_DATA) private dialogModel: ConfirmationDialogModel) {}
}

Dialog Template

<h1 mat-dialog-title *ngIf="dialogModel.Title">{{dialogModel.Title}}</h1>
<div mat-dialog-content>
  {{dialogModel.SupportingText}}
</div>
<div mat-dialog-actions>
  <button mat-button color="primary" [mat-dialog-close]="false">Cancel</button>
  <button mat-raised-button color="primary"[mat-dialog-close]="true" cdkFocusInitial>{{dialogModel.ActionButton}}</button>
</div>

Model - What is getting injected

export interface ConfirmationDialogModel {
  Title?: string;
  SupportingText: string;
  ActionButton: string;
}

Unit Test - Where I get the issue

describe('Confirmation Dialog Component', () => {

  const model: ConfirmationDialogModel = {
    ActionButton: 'Delete',
    SupportingText: 'Are you sure?',
  };

  let component: ConfirmationDialogComponent;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [
        ConfirmationDialogComponent
      ],
      imports: [
        MatButtonModule,
        MatDialogModule
      ],
      providers: [
        {
          // I was expecting this will pass the desired value
          provide: MAT_DIALOG_DATA,
          useValue: model
        }
      ]
    });

    component = TestBed.get(ConfirmationDialogComponent);
  }));

  it('should be created', async(() => {
    expect(component).toBeTruthy();
  }));
});

Karma error

Paestum

Answer 1

Try this:

describe('Confirmation Dialog Component', () => {
    
  const model: ConfirmationDialogModel = {
    ActionButton: 'Delete',
    SupportingText: 'Are you sure?',
  };
    
  let component: ConfirmationDialogComponent;
  let fixture: ComponentFixture<ConfirmationDialogComponent>;
    
  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [
        ConfirmationDialogComponent
      ],
      imports: [
        MatButtonModule,
        MatDialogModule
      ],
      providers: [
        {
          // I was expecting this will pass the desired value
          provide: MAT_DIALOG_DATA,
          useValue: model
        }
      ]
    })
      .compileComponents();
            
  }));
    
        
  beforeEach(() => {
    fixture = TestBed.createComponent(ConfirmationDialogComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });
    
  it('should be created', async(() => {
    expect(component).toBeTruthy();
  }));

  it('should close dialog when close button clicked', fakeAsync(() => {
    component.onCloseButtonClicked(0);
    fixture.detectChanges();
    tick();
    expect(mockMainDialogRef.close.calls.count()).toBe(1, 'dialog closed');
  }));
});

Preacher

In Addition, if you're using MatDialogRef in your component you need to include in in the providers array. Example: JavaScript providers: [{ provide: MatDialogRef, useValue: { close: (dialogResult: any) => { } } }] source – Streptococcus

How would I need to test something like should be closed? – Hanaper

@Hanaper I have updated the answer with the should closed unit test – Preacher

@Preacher you indeed have update the answer, although it is not evident where mockMainDialogRef is coming from. How does one obtain the ref? – Ruthenium

Answer 2

Here's an example of how to inject MAT_DIALOG_DATA in a unit test:

 import { async, ComponentFixture, TestBed } from '@angular/core/testing';
 import { MatDialogModule, MAT_DIALOG_DATA } from '@angular/material/dialog';

 import { ConfirmDialogComponent } from './confirm-dialog.component';

 describe('ConfirmDialogComponent', () => {
   let component: ConfirmDialogComponent;
   let fixture: ComponentFixture<ConfirmDialogComponent>;

   beforeEach(async(() => {
     TestBed.configureTestingModule({
       declarations: [ ConfirmDialogComponent ],
       imports: [ MatDialogModule ], // add here
       providers: [
        { provide: MAT_DIALOG_DATA, useValue: {} } // add here
      ],
    })
    .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(ConfirmDialogComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should create', () => {
    expect(component).toBeTruthy();
  });
});

Inefficiency

if my component uses the data in ngOnInit, and i have a test that wants to change that data, I run into the problem that when the test reaches ngOnInit, it still uses the default data – Amalgamate