Unit test Angular Material Dialog - How to include MAT_DIALOG_DATA

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();
  });
});

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');
  }));
});