Testing function within same file is called

I have 2 functions where one calls the other and the other returns something, but I cannot get the test to work.

Using expect(x).toHaveBeenCalledWith(someParams); expects a spy to be used, but I am unaware of how to spy on a function within the same file...

Error: : Expected a spy, but got Function.

Usage: expect().toHaveBeenCalledWith(...arguments)

Example.ts

doSomething(word: string) {
   if (word === 'hello') {
      return this.somethingElse(1);
   }
   return;
}

somethingElse(num: number) {
   var x = { "num": num };
   return x;
}

Example.spec.ts

fake = {"num": "1"};

it('should call somethingElse', () => {
    component.doSomething('hello');
    expect(component.somethingElse).toHaveBeenCalledWith(1);
});

it('should return object', () => {
    expect(component.somethingElse(1)).toEqual(fake);
});