I have an Angular service which depends on another service, which has a property, which is an object contains a method I want to spy on.

@Injectable({
    providedIn: 'root'
})
export class MyService {
    constructor(
        private secondService:SecondService,
    ) {
        this.secondService.someObj.someMethod();
    }
}

@Injectable({
    providedIn: 'root'
})
export class SecondService {
    someObj = {
        someMethod: () => {
            //do stuff
        }
    }
}

How to spy on someMethod when testing MyService?