Angular Unit Testing Going to back to previous component

In my application, I am having 3 menus, on click of any it will scroll down and showing the content of that specific menu, I am trying to go back to the previous component,

I have created mock navigation for the same.

this.window.location.hash

code to navigate to specific portion of the page,

Now i want check that if i am on section 1 and click on section 2, then i want to go back (so it should be show me section 1), please help me with this, suggest any solution.