Skip the login form and always auth as admin. FOR TEST SITES.
Skip the login form: every visitor automatically auths as an admin. FOR 'LOCALHOST' TEST SITES only, obviously, like when designing a plugin or a theme and testing it across various browsers.
For a hassle free integration, drop the plugin file into
wp-content/mu-plugins (create the directory if needed) and it will be automatically activated.
For live blogs, see Always Remember Me