Protractor with authentication

I am wondering what the best approach is to testing an angular application that has a login page and an auth guard on every other page.

Is it bad practice to make a test user and login them in at the start of the e2e test so they can access the pages without being rerouted to the login page? Are there other methods of getting around this?

The user is authenticated using firebase auth and will need to read from the real time database.

Thanks a lot.