Angular: How to mock MatDialogRef while testing

Question

I have a DialogComponent that has the following constructor where Dialog is a custom object:

constructor(
    public dialogRef: MatDialogRef<CustomDialogComponent>,
    @Inject(MAT_DIALOG_DATA) public data: Dialog
)

I created the following TestBed in Angular4:

data = new Dialog()
data.message = 'Dialog Message'

TestBed.configureTestingModule({
    imports: [MaterialModules],
    declarations: [CustomDialogComponent],
    providers: [MatDialogRef, { provide: Dialog, useValue: data }]
})

TestBed.overrideModule(BrowserDynamicTestingModule, {
    set: {
        entryComponents: [CustomDialogComponent]
    }
})
await TestBed.compileComponents()

But I get the following error:

Failed: Can't resolve all parameters for MatDialogRef: (?, ?, ?).
Error: Can't resolve all parameters for MatDialogRef: (?, ?, ?).

changing providers to:

providers: [
    { provide: MatDialogRef, useValue: {} },
    { provide: MAT_DIALOG_DATA,  useValue: data }
]

results in the following error:

Error: No provider for Dialog!

How do I resolve this?

Answer 1

I solved it by changing the component constructor to:

constructor(
  public dialogRef: MatDialogRef<CustomDialogComponent>,
  @Inject(MAT_DIALOG_DATA) public data: Dialog | any
)

The providers in the TestBed were:

providers: [{ provide: MatDialogRef, useValue: {} }, { provide: MAT_DIALOG_DATA, useValue: data }]

Answer 2

If you use at least one MatDialogRef method, you should create a mock. For example I use the close() method. Without it errors would be generated so I made the below class with an empty method.

export class MatDialogRefMock {
    close(value = '') {

    }
}

and use that instead of an empty value, with useClass

{ provide: MatDialogRef, useClass: MatDialogRefMock },

Answer 3

Import MatDialogModule and MatDialogRef from angular/material/dialog instead of angular/material. Import the ModalDialogModule and provide providers for MatDialogRef in your TestBed.

Import {MatdialogModule,MatDialogRef} from '@angular/material/dialog';

TestBed.configureTestingModule({
declarations: [componentName],
imports: [MatdialogModule],
providers: [{provide : MatDialogRef, useValue : {}}]
});