How to mock platform.backButton.subscribeWithPriority?

Ionic Framework Ionic Angular
1

Hello everyone,

I’m trying to figure out how to mock platform property “backButton” to coverage inside this.platform.backButton.subscribeWithPriority(10, () => {}).

Example of test.component.ts:

import { Platform } from '@ionic/angular';

constructor(private platform: Platform) {}

public disableBackButtonAndroid(){
  this.platform.backButton.subscribeWithPriority(10, () => {
    return;
  });
}

Example of test.component.spec.ts:

platformMock = {
      backButton: {
        subscribeWithPriority: jest.fn().mockReturnValue(of()),
      },
};

beforeEach(async () => {
        TestBed.configureTestingModule({
          declarations: [CompartilhamentoItemComponent],
          providers: [
            provideMockStore({ initialState }),
            {
                provide: Platform,
                useValue: platformMock
            },          
          ],
          schemas: [NO_ERRORS_SCHEMA],
        }).compileComponents();
});

Has anyone get success in coverage any example of a property of Platform?

Versions that I’m using:
Angular: 10;
Ionic: v5;
Unit testing framework: Jest.