To test specific roles and permissions assigned to users, create a test profile with your email address (so that you receive the password setup email), assign it a specific role and ensure that you can log in as that user.
Once this is set up, and while you're logged in as the system administrator, open an "incognito" browser window and log in as your test user - this will result in you being logged in as two users, with different roles, at the same time.
Note: screen capture from Windows and using the Google Chrome web browser. There will be similar functions when using other web browsers on either Windows or Apple Mac computers.
With your test user, assign the different roles, and edit those roles as necessary to ensure that the assigned role provides those with this role, just what you want them to do and see.